Backup/reverse light problem

**hellion** · 01-19-2010, 08:03 PM

Short background story, motor spun a bearing, just had a new one put in. After getting the new one put back in now only one reverse light works. I thought at first it was a burned out bulb, so I swapped it out with a new one, and no go. Then I noticed the one that doesn't light up when in reverse, does light up when I arm or disarm the car.

Where would those wires be crossed? Thanks

**Cutlass** · 01-20-2010, 03:09 AM

check the connection at the socket. Other than that its a very simple circuit with a fuse, a switch in the trans, and one wire back to a splice, then to the bulbs. Both bulbs even share the same ground

**Too Fast** · 01-20-2010, 04:02 AM

Just checked my car. When I use the factory remote, the reverse lights do not flash ever.

To start figuring this one out, I would first turn on the parking lights and see exactly which lights are working and which are not. Then, turn the hazards on and see if all four lamps flash in the taillights along with the taillights still working normally. There should still be no reverse lights on. Then turn it all lights off, key on, put it in reverse, and see if only the reverse lights come on and not a taillight. It's possible the socket got jambed in the wrong place and you are just now noticing a problem. (Like the reverse socket put in the taillamp housing, I've seen some really jacked-up screwups in my career.)

Hard to daignose these things from hundreds of miles away, but like Cutlass said, it really is a pretty basic circuit, I don't see how an engine install would jack up the wiring itself. Unless some hack worked on it, chopping wire harnesses along the way and not putting things back together correctly.

Good luck, hope it's something simple!

**hellion** · 01-20-2010, 11:20 AM

I didn't do a thorough test, but I went out and tested to make sure none of the tail lights came on in reverse, and none did, so it doesn't look like the plugs are swapped. As far as I can tell all of the other lights operate normally. I'll do a thorough test tonight, after it gets a little bit darker.

They did put on a new wiring harness with the motor though, not sure if that harness touches any of the wiring for the lights?

**0rion** · 01-20-2010, 11:47 AM

Originally Posted by hellion

I didn't do a thorough test, but I went out and tested to make sure none of the tail lights came on in reverse, and none did, so it doesn't look like the plugs are swapped. As far as I can tell all of the other lights operate normally. I'll do a thorough test tonight, after it gets a little bit darker.

They did put on a new wiring harness with the motor though, not sure if that harness touches any of the wiring for the lights?

I'm assuming you've checked the fuse? I'm not sure on the f-bodies where they're at as I've never had to replace one but my bet would be that it's related to the switch on the tranny or the plug/harness to that switch if the fuse checked out.

**hellion** · 01-20-2010, 12:40 PM

Originally Posted by 0rion

I'm assuming you've checked the fuse? I'm not sure on the f-bodies where they're at as I've never had to replace one but my bet would be that it's related to the switch on the tranny or the plug/harness to that switch if the fuse checked out.

I looked at the fuses last night, and the only one I saw off hand that looked related was a "Turn B/U" fuse....I'm assuming that's Back Up, but maybe not. Either way, that fuse looked fine.