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Rostra install: an idiot's addendum

38K views 45 replies 17 participants last post by  RetiredFordTech  
#1 ·
I recently installed a Rostra cruise control on my 2000 Insight. I started with the same resources that everyone else turns to:

InsightCentral.net - Honda Insight Modifications - Cruise Control 2

InsightCentral.net - Honda Insight Modifications - Cruise Control 1

While these walkthroughs were invaluable, the Rostra kit has changed a bit over the years and the instructions were not idiot proof … at least not when faced with this idiot. Hopefully the following will be a useful update for others.

Ordering the Kit

I ordered the following part numbers from Brandon Distributing (877-402-3944) Brandon Distributing, Inc. - Accessories for your Car, Truck, SUV & RV :

250-1223

250-1483

250-4325

Joe Brandenburg was very helpful and the total cost came to $262.95.

Opening the Boxes

The basic components are easy to identify. The intimidating part comes when one looks at the baggies full of tiny parts. Know this up front: lots of these bits and pieces are not used.

Under the Hood

After you install the cable bracket and throttle adapter per the linked instructions, you need to prepare the cruise module’s throttle cable for use with the snap-in adapter (G-17). In order to use it you need to add threads to the throttle cable. Use one of the small lock nuts that comes with the kit (G-15) and a box end wrench to score about six inches of threads on the cable. Remove the lock nut and then thread on the snap-in adapter about half way up the newly scored throttle cable with the top of the pyramid pointing towards the end of the throttle cable. Next you need to prepare the end of the throttle cable to attach to the throttle adapter. The linked instructions are very good, but the current version of the kit is a little different. First, you do not need to use the bead chain on this version of the control unit as it automatically compensates for slack. The eyelet connector (G-8 ), one bead connector (G-4) and a cotter pin (G-16) are the only parts you need to attach the cruise control’s throttle cable to the throttle adapter in the current version of the kit. Many of the orphaned bits and pieces come from this step.

After the throttle cable is ready, snap the adapter (G-17) in to the cable guide. The eyelet connector should slip over the throttle adapter easily; in fact, the eyelet is pretty loose on the adapter. Before you install the cotter pin, make sure that the cable does not have too much slack. The goal is to have the same amount of slack as engine’s throttle cable. The slack is adjusted by varying the position of the snap-in connector on the throttle cable through trial and error. I started out with the snap-in connector threaded about three inches up on the throttle and had move it down another half of a inch to get the desired tension. Finish by inserting and securing the cotter pin on the throttle adapter.

After you mount the cruise control module (I used the supplied bracket; electrolysis be damned … I’m a rebel like that), and attach the ground wire and plug in the wiring harness, you are basically finished under the hood. If you haven’t already had a beer, now is a good time to get one.

Under the Dash

Per the linked instructions, start by removing the grommet on the heater control cable and running the two four wire connectors that you’ve removed from the wiring harness through this hole from the inside of the car to the engine bay. This is a very frustrating process. Take your time.

On my MT Insight, I had to install a clutch switch. The same quirk as noted in the instructions still exists on the latest kit in that you need to cut the two-prong connector from the switch and then connect the violet wire to one of the wires and the then tap into the brake light negative wire (green/white) with the other. I had to add some wire to the clutch switch in order to reach the brake light negative wire. The red wire from the harness then taps into the brake light positive wire (white/green).

I used the fuse for the accessory plug to tap for power (brown wire with the spade end on the wiring harness). I then tapped that same brown wire with the brown wire from the RF control. I made this tap after the in-line fuse.

The blue wire still isn’t used. I attached it to ground along with the ground wire from the RF control.

The gray VSS wire is still attached to the blue/white wire on the 31 pin blue connector under the passenger side floor. This connector is towards the outside (right) of the car. Unplug it and cut away some of the insulation to get enough slack to use one of the Scotch connectors (G-22).

On my version of the RF control there is a two-prong plug that I didn’t use. There is also a plug on the wiring harness in the engine bay that I didn’t use. Just leave them hanging; the system works fine without connecting them to anything.

Hope this helps.
 
#3 ·
250-1223 - Cruise control module

250-1483 - RF Switch

250-4325 - Adapter

I placed my order by phone/email.

As for pictures, the linked instructions provide good images. If you need something in particular, just post or PM and I'll help out if I can.
 
#5 ·
I installed mine over a couple of days and then a week went by while I had to trouble shoot a wiring problem (spoiler alert: it was the VSS wire, natch). I drove the car off and on the entire time.

You will have to exercise some common sense obviously. After you attach the cruise control throttle cable, make sure that you've adjusted the slack properly before you drive. Otherwise, as long as everything is secured and out of the way, you can drive the car before finishing the job.

If you are doing this in stages, then the point at which I recommend getting a beer is a good stopping place. At that point, you've finished installing everything under the hood. Other than the ground wire, you haven't hooked up any wires and the cruise control unit will not interfere with the normal driving of the car in this state. Just use common sense and make sure that everything is out of the way, i.e., no bits dangling near drive belts or sources of extreme heat like the cat or exhaust manifold.

As for the wiring, as long as you use the included Scotch taps, you won't be cutting any wires that are native to the car, so you should be OK. Once you start the wiring work, I wouldn't drive the car until after all the ground wires are in place.
 
#6 ·
Per the linked instructions, start by removing the grommet on the heater control cable and running the two four wire connectors that you’ve removed from the wiring harness through this hole from the inside of the car to the engine bay.
I am at this stage of the Rostra installation and would like some clarification.

Did you somehow pull the heater control cable grommet into the inside of the car or did you pop it out of its hole from under the hood? Access from the engine compartment seems very difficult. But pulling it inside the car also seems like it might be difficult because it's recessed a bit with access being a hole about the same size as the grommet.

Do the two 4-wire connectors end up in the engine compartment? If so, is there sufficient harness length inside the car to make all necessary connections?

Did you run the cruise control harness through the grommet and then insert the grommet back in its firewall hole? With both the heater control cable and cruise control harness wiring in the grommet, I would think that putting it back in its firewall hole would be difficult.

Any tips or suggestions would be welcome!
 
#9 ·
I pulled the grommet from inside the car with needle nose pliers. It didn't tear or deform and could be reused.

As for the connectors, yes, they end up in the engine compartment and I had more than enough wiring length inside the car except for the one instance that I noted re: the clutch switch.

The grommet is just hanging out on the heater control cable. I didn't see how to reinstall it with the additional wiring now occupying the hole. I haven't had any problem with water intrusion. This seems to be par for the course. From the instructions I linked to before:

Replacement of the Honda heater valve control cable firewall grommet with a generic grommet provided the firewall pass-through I needed (sealed with silicone caulk). In fact, I left the original grommet on the heater valve cable. If I remove the cruise control, the grommet will slide right back where it came from, restoring the original configuration. Super.
As I recall, I did take some precaution to prevent chaffing, but that was it.

Hang in there. It's frustrating, but the system works pretty well once it's installed.
 
#8 ·
For the people with the plug and play MIMA harness, you can pick up the VSS wire on the distribution board.
Thanks for the tip! I was at least clever enough to realize that both the Rostra and MIMA required ECM access, so I had planned to install the MIMA ECM components when I tapped into the VSS wire at the ECM for the Rostra. But now I'll plan to install the MIMA distribution board as well so that I can tap into the VSS signal there.

Now if only I could get some warm weather so my fingers will function while performing these installations… <looks outside at snow flurries :mad:>
 
#15 ·
I would like to make some installation comments that might help any Insight owner who might still be considering installing a Rostra cruise control (unless I'm the last one to do so :) A big mahalo to those who posted their installation instructions previously because they made what would likely have been a difficult installation possible for us mere mortals.

Under the Dash

Lying on my back on the floor of a car under the dash is one of my least favorite activities. So I prepared the under-dash portion of the wiring harness as much as possible prior to crawling under the dash.

I plugged the short RF control wiring harness into the main wiring harness. Unlike bciesq's RF control wiring harness, mine did not have an unused 2-prong connector. It did have an unused 1-prong connector attached to an orange wire which is apparently used only for troubleshooting. It also had a black ground wire and a brown +12V. wire. My main wiring harness had an unused 2-prong connector marked "TO CONTROL SWITCH (6-PIN ONLY)". The black wire in this connector is a ground wire and the light blue wire, +12V. So I cut off the connector and soldered these wires to the ground and +12V. wires from the RF control wiring harness and insulated the soldered sections with short pieces of heat-shrinkable insulation tubing.

Because the wiring harness' blue tach wire is not used, I shortened it so that its length was appropriate to connect it, using one of the self-strip connectors (G-20), to the black ground wires that I had just soldered together.

I cut off the clutch switch connector and soldered one of the switch's wires to the violet "brake negative" wire of the wiring harness. I soldered a length of wire cut off earlier from the wiring harness to the other clutch switch wire based on bciesq's suggestion to lengthen this wire.

Because I was also installing a MIMA at the same time, I shortened the wiring harness' gray VSS wire and soldered it to pin 12 of the MCM connector of the MIMA distribution board as suggested by Mike rather than tapping into the VSS wire at the ECM plug.

The attached photo shows my modified under-dash wiring harness. Only the brown +12v. power wire, the red "brake positive" wire, and the clutch switch positive wire will need to be connected under the dash.

After a frustrating hour trying to stuff both wiring harness connectors through the heater control cable firewall hole, I decided that I needed to modify the connector that I was unable to push through the firewall hole. This connector, the second down from the top left of the attached photo, has a small raised ridge around its circumference about mid-way along its length. This ridge was hanging up on the firewall hole and doesn't seem to be important. With a pocket knife, I carved away sections of this ridge on the side opposite the slot through which the matching connector's lock tab passes. I also trimmed back this ridge immediately adjacent to the lock slot so that the connector could lie as closely as possible to the heater control cable. With these modifications, I was able to push both connectors through the firewall hole.

Under the Hood

I was not comfortable routing the throttle cable from the cruise module over the top of the battery. So I curved the cable back toward the firewall at its cruise module end and curved it back toward the front of the car so that it rests against the passenger side of the battery box where I secured it with zip ties. It then passes below the driver's side end of the engine cover so that it is not very visible.

My connection of the throttle cable to the throttle adaptor was slightly different than described by bciesq. I used an eyelet connector (G-8 ), a connector cover (G-5), a cotter pin (G-16), and two flat washers that were extra parts not needed elsewhere in the installation; I found no need to use a bead connector (G-4). I placed the flat washers on either side of the eyelet connector when I attached the eyelet connector to the throttle adaptor. This certainly isn't necessary, but I thought that having these washers on either side of the eyelet connector would separate the eyelet connector from the cotter pin and the throttle adaptor which might make the connection work better in the long run.

After connecting the under-dash and engine-compartment sections of the wiring harness, I used silicone rubber to seal the back side of each connector where the wiring emerges to prevent water from possibly corroding the wiring pins. I stuffed the sealing putty that was included with the Rostra kit in the firewall hole around the wiring harness and heater control cable to prevent water from entering the passenger compartment.

The cruise control seems to be operating normally, but I need to test it more on the highway.
 

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#16 ·
Well, my new Rostra cruise control worked for about 10 miles then stopped working :-( Pressing any of the controls does nothing. Because it had worked fine briefly, my first guess was that a bad connection was the culprit. The primary suspect was the main +12 v. connection which was made with a long, thin spade-like connector designed to be inserted alongside the hot prong of the accessory socket fuse. With the fuse plugged in, the spade connector seemed loose. So I used one of the included Scotch connectors to splice the brown Rostra +12 v. wire into the white/black wire connecting the ignition switch "on" (i.e., position III) with the under-dash fuse panel. Unfortunately, this did not solve the problem. I verified that the main Rostra 10 amp fuse in the +12 v. brown wire is not blown and is at +12 v. when the ignition is on.

The Rostra installation manuals include self-diagnostic instructions which require reading a LED adjacent to the 12 programming switches in the cruise control module in the engine compartment. This switch is recessed in the cruise control module housing. Shining a light into this dark recess reveals no obvious LED. When I had my wife enter the self-diagnostic test mode (turn on the ignition while depressing the RESUME/ACCEL button), I looked into this recess hoping to see the LED illuminate as it should according to the instructions. But I saw nothing. That in itself could point to certain potential problems.

However, I can't see any LED, so I wonder whether the LED location has been changed without the instructions having been updated. Have you used the Rostra self-diagnostic procedure coupled with the wireless controller? If so, can you tell me whether the diagnostic LED was where it is documented to be (i.e., adjacent to the #1 programming switch)?
 
#17 ·
Well, my new Rostra cruise control worked for about 10 miles then stopped working :-( Pressing any of the controls does nothing. Because it had worked fine briefly, my first guess was that a bad connection was the culprit. The primary suspect was the main +12 v. connection which was made with a long, thin spade-like connector designed to be inserted alongside the hot prong of the accessory socket fuse. With the fuse plugged in, the spade connector seemed loose. So I used one of the included Scotch connectors to splice the brown Rostra +12 v. wire into the white/black wire connecting the ignition switch "on" (i.e., position III) with the under-dash fuse panel. Unfortunately, this did not solve the problem. I verified that the main Rostra 10 amp fuse in the +12 v. brown wire is not blown and is at +12 v. when the ignition is on.
Well, my attempt to improve the intermittent +12 v. Rostra power connection by replacing the spade connector with a Scotch connector splice failed. Even though I measured +12 v. at the power wire's inline fuse, the connection was apparently intermittent. When I inspected the splice, I found that the Scotch connector had opened up allowing the ignition-to-fuse panel wire to escape. I reattached the Scotch connector and taped it shut in hopes that it won't open again. The connector is in a cramped area adjacent to several other fairly large, stiff wires in the car's wiring harness, so it isn't an ideal location for a splice.

After reconnecting the Rostra's power wire, the cruise control functions normally again. Testing it while in PIMA mode adjusted to provide aggressive assist when climbing hills and aggressive regen when descending hills thus keeping the fuel consumption rate fairly constant and low (i.e., maximizing lean burn time) indicates that my Insight should attain good fuel economy without much manual intervention from me. Nice combo!
 
#18 · (Edited)
Just installed the ROSTRA CRUISE CONTROL.
Saved half the cost of buying from the suggested retailer and performing a DIY installation vs. retail local prices complete with install. The angle aluminum bracket used to secure the unit as seen in the linked photo was home made from plans searchable on this site.

[THIS CC IS 'OLD' NOW with DIP switches buried away,>>>> CHECK brandondist [no affil] for their newer "gain adjustable from cabin" model ['500' version for cable throttle]]. ask for JOE.

The installation involved 'some degree' of discomfort working under the dash as others report, but was straightforward for the most of it. I didn't solder but used crimp-on connectors and a couple morettes well taped.
The Rostra wiring harness connections through the firewall went well for me by slipping the male half of each connector through from each side of the firewall to the other side. I had seen this in another vehicles factory installed harness passing through the firewall.
tl/dr
[With one harness connector on each of both sides of the firewall, this avoids pushing through the Rostra female connector through the too small stock existing hole by trimming it or by enlarging the hole.]

[Wrapped the connections going through the firewall with polyethylene plastic, next electrical tape, then jammed a helical cut [5"] rubber gas line hose through the hole in the firewall bulkhead and slipped it/wrapped it over the short length of wires between the two connectors. Taped the helical cut hose up best as could from each side of the firewall. Fit was tight and buildup of electrical tape each side keeps it located.
The slit rubber hose with tape encasing the wires acts as excellent protection from chaffing through the hole in the firewall plus it seals well. The harness was zip tied well clear of the steering mechanism and heat in the engine bay area, and tied up into the underneath of the dash area zimilarly.]

For the VSS vehicle speed sensor connection, removing the bolts holding the ecu to the plate under the passengers kick panel , so to give wires some freedom of movement, and untaping/unraveling/unbending the wire harness made tapping into the VSS wire in the vehicles harness easier for me. I tied in a few inches up from the ECU where some slack could be had using a crimp on type connector .

The 12V+ accessory connection at the fuse box [#12] was loose on the first attempt on my installation test drive, so I plugged it in more securely and all was well on the second test trip around the block.
[That was after figuring you have to "push and hold" the cruise control's remote 'on' button at the initiation of cruise control, and then wait sec or so for the unit to judge a speed vs just one quick click.]

Driving using the cruise showed there was a bit more variation in the speed than I'd figured [or I was used to from more powerful vehicles in the past that maintain speed easier], but I attributed this to the Wt/HP ratio of the Insight, and top end gear selection on grades; or possibly the slack in the cable setup, [though the latter proved to be not the case]. In newer Rostra units, slack in the cable is automatically adjusted so all was well.

The Rostra CC was working well enough on the settings it arrived with [except for switching from 'auto' to 'manual' dip switch] but still I wondered:
Q: Had anyone changed up the rate of response via the DIP switch settings?
I was ok at first with it on 'medium' gain sensitivity, but I was thinking 'low' setting might preserve the lean burn longer and 'fast' keep road speed better at the expense of economy.
Edit: I recently opted for the 'extra low' setting.
______________________
In as much as there's a power limitation of the Insight itself, and it's prone to loss of speed, the Rostra Cruise Control works well enough on the flat without a headwind, ± a few kph. Long trips are easier on leg strain if not necessarily giving optimal fuel efficiency.
I obey gravity generally, and pick my spots and/or shift the transmission and resume cruise to prevent greater loss of fuel economy.
I informally tested the mileage on a few long trips cross country, but wasn't rigorous, and although road conditions were inconsistent on the trips, could see right away from the Scangauge, that lean burn indications were fewer under cruise control. To pull a number out of my hat, I'd guess ten percent rough estimate, not much really in terms of cost overall, but significant if trying to maintain a good segment mileage.

[Basically:
The cruise control definitely makes long hundreds of kilometer trips much more comfortable, and if used in the proper road conditions with proper gear selection isn't overly harmful to fuel economy.]

_________________________________ [27.09.11]
The sensitivity of the gain of the control can be adjusted via dip switch settings #1 and #2 located under a rectangular rubber plug on the base of the Rostra Control. Both switches were set to "off" to program in the 'extra low' gain sensitivity.
From the install manual:
"Gain is how the cruise reacts to road conditions and motor size. Always start a Mid gain. [unit was preset in Mid] If vehicle surges, change gain. For [to correct the problem of] a fast surge, switch to a low or extra low gain setting if needed to tune the cruise. If there is a slow surge, switch to high gain."
The application of throttle is softer and slower [ although the same range of TPS inputs was observed on acceleration ] via observing the ScangaugeII accessory monitor.
The higher the gain [High, Medium, Low, Extra Low], the closer the 'set' road speed will be maintained; plus the greater the fluctuations in Throttle Position TPS changes that affect lean burn and lessen economy. My unit arrived set to 'medium' in positions 1&2 DIP Switch positions.
__________________________
In answer to another post elsewhere on the forum where it was wondered what would happen if the 'engine/setup timer' was set for one of the settings on '6 cylinder', vs. '4,low', the helpful Rostra Tech at their toll free line indicated this would make the surge and fluctuation of throttle and speed on initiation of cruise control _worse_ on our tiny 995cc engines.
"Engine/Setup timer is how fast the cruise retracts cable in on set. "
He told that for some V8 engines, with experimentation in tuning the CC unit, in order to make the Rostra controller onset smooth, he got best results setting the engine/timer setup as a '4,low'.
________________________
The Insight will work best at the lowest settings possible: for how fast the Rostra Control pulls the cable [engine/setup timer]; and likewise lowest settings for how the controller reacts to changes in road speed due to road conditions and the first generation Honda Insight's power to weight ratio.
________________________

When I use the Rostra Cruise Control for reason of comfort, I now push and hold the 'set/decel button to activate the unit when accelerating using the foot; release the button at the desired speed; then lift the foot smoothly off the accelerator.
_______________
After a couple months the Cruise Control would switch itself off occasionally, then it finally quit:
Due to an unknown erratic connection that after time may have worked loose where I'd merely inserted the wires into the back of the brake switch connection, I re-did them using crimp-on connections a short ways up the line. At the same time I made the ground connection better using a couple large washers to sandwich the eyelet connector for better contact to the dashboard frame at the screw under the storage box beside the hood release. I suspect the ground working loose from flexing when the hood release was actuated, but possibly the brake connections had worked loose from vibrations. The harness and remote receiver was tightly re-secured under the dash using snap ties for good support.
===============================
The Rostra cruise control unit is working well as can be expected, and seems to run in lean burn a bit better with the lowered dip settngs, but as with other cruise controls, less well than under driver control for optimal economy.
 
#19 ·
The erratic Rostra Cruise Control's recent operation problem finally turned out today to be a poor connection at the fuse box.
The rostra's wires at the brake connection, well jammed in, plus the ground connection at the original point of attachment, were likely OK.
A new battery for the remote was also purchased just in case, as a weak battery in that component will shut the unit down so read the instructions.

What fixed the problem was I changed the power connection up from the original Rostra provided thin flat shoe-horn like connector [a thin metal strip intended to slip alongside a leg of the fuse inserted into the fusebox] to Littlefuse Inc.'s "Add-A-Circuit" accessory power source fuse box plug-in p/n #FHM200BP.

It seemed obvious in hindsight, but the on-again, off-again nature of the lack of function proved tricky. Leastways all connections are now secure.

This addition of a 10A fused adapter costing about $16, solved the all the erratic electrical problems [ due to periodic vibration/oxidation of and/or poor fit of the rostra connector to the MINI fuses used in the Insight].

The 'Add-A-Circuit' fusebox plug-in provides a solid, fused electrical connection much superior to that provided more in keeping with the other parts provided in the Rostra 250-1223 kit.

I would encourage people to replace the stock connector provided, with the 'Add-A-Circuit' fused connection or similar product for accessories to assure reliable function and save some effort working in the confined area under the dash.
 
#20 · (Edited)
What did you all do with the throttle pulley cover? I put the conversion piece provided by Rostra (first pic) and it seems to rub the plastic cover and even got stuck with the throttle open in one test of mine. I thought about cutting out some of the cover (third pic) but wanted to see if anyone else had this issue.
 

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#21 · (Edited)
Throttle cover is removed with Rostra installation

What did you all do with the throttle pulley cover?
I just set it aside on a shelf with the bolt taped to it in case ever needing it again. Instructions for installing the kit called for the removal of the dust cover.
It's not intended to be re-installed over the added arm and cable setup for the Rostra kit.
==================================
EDIT: same also borne out in comment here
"Once removed, I stored it away in my spare parts bin because it won't fit back on with the Rostra throttle adapter in place."
 
#22 ·
I cut a small section out of the cover so that I could reinstall it to help keep the pulley and cable from accumulating too much dirt, oil, road contamination, etc. I kept the small pieces that I cut out in the very unlikely case that I ever uninstall my cruise control. I could just glue these pieces back in their original locations.
 
#24 ·
Did anyone take nice pretty pictures of their wiring work? I'd like to see how you kept all the wires nice a tidy and where exactly you put them. Where did you all put the brown acc wire? I was thinking the power windows in the interior fuse box, any objections to that?
 
#26 · (Edited)
I just installed mine, thanks so much to everyone else's reports, it worked on the first try!

Here's a few things I've got to add.

Despite all the explanations, it still took me a while to figure out the throttle attachment.
The needed parts are:
CONNECTOR COVER
EYELET CONNECTOR (The Rostra throttle adapter instructions incorrectly say BEAD CHAIN CONNECTOR)
COTTER PIN


Assembled like so:

and attached to the Throttle adapter bracket with the cotter pin.

Trying to put the wiring through the firewall alongside the heater cable is ludicrously more difficult than it ought to be. I found an unused grommet right above the ECM and used that instead. I don't have A/C or CVT, so perhaps it's not empty for everyone. Still, I'd be pretty surprised if there wasn't another available grommet somewhere else.
I removed the grommet, cut out the center and made a slit in the side. It fits perfectly around the supplied split loom tubing.
 
#28 · (Edited)
So i have a question that has not been answered yet that i could find.

As a lot of people i have been having problems with the VSS wire. I tried to wire the Rostra vss wire to the factory vss wire at the ECU and the wiring was good but the car was not showing a speed when i test drove it. So i took some of the peoples advice on these forums and wired it at the vss wire in the engine bay and the same exact thing happened, no displayed speed when test driven. When i remove the rostra vss wire and rewire the stock wire i have my speedo telling me the speed again.

I leave for a 3,000 mile trip tomorrow and i need help fixing this problem by then. Having cruise control is extremely important for me as i will be pulling very long hours. Any advice that i can try would be incredibly appreciated.

My guess is it is drawing to much current and the wire then can't completely send its message to both rostra and the insight?

Thanks!!
 
#29 ·
It's not sa fix but as a work around stop gap you can download a GPS based speedometer app for your smart phone and use that and the Cruise until you get a real fix.
 
#31 ·
Are you sure you are on the correct wire? I've installed a number of the units and never had a problem.

Scott
 
#32 ·
I followed an online writeup that is on this forum and used the grey wire to go into the blue wire with a white stripe. What could it be? I just need some things to check. It is a weird thing for sure.

But whenever it is wired in it doesn't show mph on the dash. I have removed the grey wire and it started showing mph again
 
#33 ·
From my photobucket: more pics in Rostra link in sig. [The only prob i had was with the stock rostra spadefoot to the minifuse for power <<replace it. ]
Image

To determine vehicle speed the Rostra gets the pulses from the VSS wire located at number five position of the thirty-one pin blue connector on the ECU. After the ecu was unbolted from the passenger kick-plate under the floor by removing first the four 10mm nuts holding the plate, then the remaining two 10mm bolts securing it, the 31 pin blue connector was removed from the ECU and the coiled loom unwound a bit to better get at the #5 pin blue/white wire that runs up the vehicles harness. The red tap connection right of center [VSS] holds the gray wire from the Rostra harness and the vehicle's speed signal wire a few inches up the harness from the blue 31-connection. The tap was well taped before folding it up and reinstalling in that tight location. The excess gray harness wire was left uncut and loosely coiled under the plate. It was then time to test drive and final zip tie and wrap the harness, and replace panels etc.
 
#36 ·
To determine vehicle speed the Rostra gets the pulses from the VSS wire located at number five position of the thirty-one pin blue connector on the ECU. After the ecu was unbolted from the passenger kick-plate under the floor by removing first the four 10mm nuts holding the plate, then the remaining two 10mm bolts securing it, the 31 pin blue connector was removed from the ECU and the coiled loom unwound a bit to better get at the #5 pin blue/white wire that runs up the vehicles harness. The red tap connection right of center [VSS] holds the gray wire from the Rostra harness and the vehicle's speed signal wire a few inches up the harness from the blue 31-connection. The tap was well taped before folding it up and reinstalling in that tight location. The excess gray harness wire was left uncut and loosely coiled under the plate. It was then time to test drive and final zip tie and wrap the harness, and replace panels etc.
I'm in the process of installing this kit. After I opened up this panel in the floor of the passenger side and looked at the pins. Pin 5 is White/black and Pin 6 is Blue/White. Is there a difference in year to year wiring (I have a 2002 automatic).

I just want to be sure before connecting to the wrong wire.
 
#35 ·
Maybe too late before the trip, but perhaps it's the DIP switch settings for VSS: On inside of rostra actuator unit under the rubber cover, there is a DIP#10 that should be ON for square wave form vs. sine waves. Not clear how that may alter things.
[photo of DIP Switch Settings I used initially, included with description in my sig. link]

Image

[Please ignore my sensitivity gain settings DIP1 DIP2 off = extra low chosen to lower TPS response for more LB lean burn. I'd choose a higher gain setting then shown for quicker ICE throttle increase. That should count for better and safer 'roadability' and less battery drain - for my car low throttle gain was moot, Mima allowed disabling stock IMA so drain under CC was not an issue.]
 
#37 ·
I think you're counting from the wrong end. Pin 5 is the blue/white one. That's the one to use. (The first 3 pins are blank, #4 is white.) Pin 6 (5 pins from the other end) is white/black. Don't use this one. The colors are the same for all years.

Sam
 
#39 ·
Interesting. I didn't see ANY numbers on mine when I did it a couple of weeks ago. I just looked at the colors and positions. The colors and positions I just quoted are from the Honda Electrical Troubleshooting manual.

But, yes, definitely use the blue/white wire, which is between the white and white/black ones.

Sam
 
#41 ·
Interesting. Either the plug marking is wrong, or the Honda manual is wrong. Whatever, the wires are where they are supposed to be, regardless of the numbering.

Sam