[Craigjoplin1959]

G1 didn't have temperature knob upon purchase. Got new one from Honda. Knob slides on about 1/4". It doesn't take much to knock it off.

I pressed firmly to see if it seat deeper. It doesn't.

 

[retepsnikrep]

Glue it on?

 

[bbcb]

Check the post sticking out of the dash. I bet the sleeve from the old (broken) knob wasn't removed by the previous owner, hence you cannot fully install your new knob.

The sleeve can be pulled off with pliers.

 

[Craigjoplin1959]

It was the thin metal sleeve. Being recessed into the unit made it unnoticeable. Once informed and a close look I could see it. Snagged it with my finger nail.
Thank you for the replies.