metroplex

I have a 09 SS/TC and it seems the gear indicator/sensor is no longer working. When I shift into reverse, the white reverse lights don't seem to work because I cannot see their reflection on the wall/street. In addition, my reprogrammable performance display (RPD) no longer shows the gear I am in nor does it display the shift light indicator.

Is there a gear indicator or sensor inside the F35 that might be bad, or is this an external sensor I can replace?

DillySS

Check fuses?

R4race

that would be BCKUP in the underhood fuseblock

pretty simple circuit, fuse, switch, splice, lights

metroplex

The 10A fuse is good, but it looks like the switch is FUBAR. The bulbs aren't lighting up and I can't get 12V at the bulb sockets.

I can't find the switch on the transaxle, any idea where it is on the MU3/F35? I am not sure how it is related to the other gear indicators and the RPD, but it'd be nice if I can get my backup lights working again. RockAuto listed an AC Delco switch ($10) for the MU3.

Maven

iTrader: (1)

Damn, how many threads are you gonna make about this?!?!?

If for some reason taking it to the dealer is out of question do the following.

Chk the fuse in the underhood fuse block.
Chk BOTH bulbs, make sure they are good.
Chk to make sure the reverse switch is plugged in, its on the top of the trans sticking straight up, has two wires(pink and light green)

If its plugged in, disconnect it and make the the terminals in the switch are straight, and the terminals in the connector look "tight" and not all expanded.

This should end your driveway diagnosis. If you MUST go a step further,
Turn the key all the way(not running) use a low impedance test light to test for B+ at the pink wire. If no B+ youve got problem between the connector and the fuse block. If youve got B+ there, use a fused jumper wire and connect the pink wire to the green wire. If your lights now work youve got a bad switch, if they dont youve got a problem between the switch connector and the ground circuit for the lights at the rear of car.

If there was any of this you didnt understand....DO NOT ATTEMPT ANY REPAIRS OR DIAGNOSIS, take it to a dealer.

Dont buy a switch, theres a reason you have a warranty.

metroplex

Fuse is good, bulbs are good, it's not getting +12V at the bulbs.

I cannot find the backup switch on the trans. My Haynes shows it above the left driveaxle (05-07 MU3/F35) but GM's 2009 pic of the F35 shows that the housing looks very different. Where do I find this switch? Is it closer to the engine block or closer to the fender?



I understand what you're saying, your recommended steps are to isolate the problem at either the switch or the wiring leading to the actual bulbs. I just can't find the switch to begin trouble shooting. I don't recall the reverse lights ever working to begin with.

FWIW, it's a $10 switch, and it'd be a waste of my time to take it to the dealership, argue with them, and have them fix it and find grease and grime all over the interior.

Thanks.

Maven

iTrader: (1)

Switch isnt in that pic, but it goes here. Right on top. Look down at the trans, its the only switch youll see.

metroplex

Roger that, I'll go and take a look. The fusebox and other stuff is in the way, IIRC.

metroplex

Maven: It turns out that the switch wasn't installed properly. Someone at the factory must not have torqued down the switch. enough. The ball detent wouldn't trigger the internal contacts since the pawl couldn't depress the detent.

I also found out the driver's rear bulb wouldn't work because the bulb contact was bent! It's working now. Thanks for telling me where to find the switch.

Maven

iTrader: (1)