Originally Posted by clahy
The fan is working you can hear it run
That is not conclusive.
Is that during charging or during driving? Driving for 30 minutes before an IMA light is easily the amount of time needed for the battery to heat to the point that the fan is powered on by the car. Car commands fan on, but it doesn't get feedback. Code.
Did you check the grid charger harness as I recommended? Are all the connections intact? You have a piece of hardware between the car and the fan. You need to lay eyes and hands on it. Period.
The HA fan harness is pass-through. It will drive it even if the car can't. It just depends on the connections and circuitry being intact. If any of the four connections on the car side are broken, the grid charger will still run the fan, but the car won't.
Inspect the harness. If you have any broken wires or loose connections, you have a problem. If you find nothing, completely remove the fan harness from the circuit to restore the car to original. If the code goes away, put the harness back on. If it comes back, it's the harness.
If the code comes back w/o the harness installed, then you need to conduct the diagnostics outlined in the link I provided.
I have seen ONE HA harness that had a broken connection in exactly this fashion.