No backup lights

**rickisrad** · 01-11-2018

My backup lights are not working. The fuses are good and I’m not getting power to the harness. Where in the heck is the sensor on these? I’ve never had this issue on any of my past Prix. Any help appreciated.

**rickisrad** · 01-11-2018

Mods- I meant to post this in general section. Sorry

**Scottydoggs** · 01-11-2018

check the trunk harness it likes to break where it comes through the body by the hinge.

**wstefan20** · 01-11-2018

By no power, where did you measure? It's very common for the wires to corrode through several inches. Test the wire on the right rear tail a few inches back.

**rickisrad** · 01-11-2018

I tested at the harness in the trunk that attaches to the backup lamp bar.

**wstefan20** · 01-12-2018

Strange... best place I've found for schematics on our cars is actually autozone. Just register for a free account, search under repair guides, wiring diagrams and there's the diagrams for literally every system in both newer gens of our GPs! Watch out, some of the colors may not be correct, but if you can read the connector positions, I've never seen one wrong yet! I'll take a look some-time and see what I can think of.

In the meantime, are there any other issues or lights (especially interior) that are not functioning properly?

**wstefan20** · 01-12-2018

Looks like the bcm controls the backup lamp relay. Probably under the driver's dash, but I'm sure someone will chime in on the exact location.

Before I tested that, I would do a power drop test to test the ground to make sure you don't have a bad ground to the lamp, but I wouldn't think so since pretty much the whole rear end is tied to that ground.

Here's the schematic I found on autozone for the backup lamps for an 05 which should be the same. If the ground is good, I'd test the relay.

**wstefan20** · 01-12-2018

There's no direct sensor for these. They are triggered through the bcm indirectly by the range selector switch, but there's a relay that controls the lamp inbetween. I'd test for good ground, then go on to test the power coming from the relay. If that's good, I'd test the continuity of the power wire and then have fun locating the break. Might just be a bad relay though. Posted the schematic on your other post if you want to check it out. Autozone has all the schematics you'll ever need.

**rickisrad** · 01-12-2018

Thanks guys. I will check these things out soon. This winter storm is bad right now. Went from 57 to 22 in a few hours. Went from heavy rain to solid ice and now snow covering it all. Gotta love it.

**Scottydoggs** · 01-12-2018

i replied in the first thread, no idea if you ever looked back at it.

its the trunk harness, where it goes through the body near the hinge. open that up and you'll find a bad wire, theres also a plug in the trunk to unplug the harness, that plug might be boogered up. the lic plate lights work? if not its the harness too.

**rickisrad** · 01-13-2018

First thread? Is there two of them? Weird. As soon as I can get into the trunk to look I will check that out. Everything is frozen shut with ice now. Thanks!!

**Scottydoggs** · 01-13-2018

No backup lights- 2007 GT aka your first thread.

**rickisrad** · 01-13-2018

Lol. I didn’t make 2. A mod might have moved one and didn’t delete the original. I will try to delete the one with the least replies.

**Scottydoggs** · 01-13-2018

you made two in the tranny section. either way, that harness is a very common failure point for anything mounted in the trunk thats not working.

**rickisrad** · 01-13-2018

I will definitely check that out.

It it must have been a glitch. I didn’t purposely make two threads. I’m trying to figure out how to delete one of them. I might have to do it on my PC instead of phone???

**Scottydoggs** · 01-13-2018

you cant delete em. only mods can. dont matter, get to hunting on that harness lol

**BrandonHall10** · 01-13-2018

Originally Posted by rickisrad

Mods- I meant to post this in general section. Sorry

Moved.

**rickisrad** · 01-14-2018

Thanks Brandon.

I went out to trace the wires and and it is too darn cold out. I will have to move some crap out of the garage so I can get the car into some heat.

**Scottydoggs** · 01-14-2018

on my regal the plug is behind the side cover, follow it inside, unplug it, then pull it out the grommet, open the loom starting where it looks pinched, cause thats where the busted wire will be found.