My reverse lights aren't working and we traced it back to the sensor in the transmission ('88 5 speed). But we cant get the sensor out of the transmission case.

We are guessing it is a 20mm wrench (which we don't have) but we are not sure if it screws off or pops off.
We obviously don't want to break it and are unsure how to do it properly.

We've ruled out the bulb and the fuse already.
Has anyone had this off before, and if so, how?

-Paul

it unscrews. soak it a while with some pb blaster. it's in a rough spot to get at, mine came out fairly easy. I take it you confirmed the switch is bad by shorting the 2 wires in the connector where it goes back into the harness?

Search the parts stores for the 89 either cavalier or celebrity with 5 spd, that part still lists and is available.