Hi all, been doing some research on this issue and while I've not come across someone with the exact issue as me, I have some ideas as to what might be the cause, but just looking for some thoughts as to what others think is going on.

My reverse lights work, but are insanely dim. I tried incandescent and LEDs, both are wildly dim. This is my second C5 and the reverse lights on my previous were significantly brighter. The lights work with FOB and in reverse and have been dim since the day I bought it. I have noticed some flickering as well, although it is intermittent and not constant. I've also noticed that with one the LED bulbs, it would only light up (still dimly) when the other side did not contain a bulb. Not sure if that bulb drew more power than the ones I currently have in there or why that was the case.

First thought is it could be a fuse issue. I've seen that several fuses are involved in the B/U lights, however, my DRLs and Rearview mirror both work as they should, eliminating some of the fuses as the culprit. Similarly, since the lights work in reverse, I believe that the switch on the transmission can also be eliminated as the culprit. That leave fuse 38, which I'll be checking this weekend.

Second thought is lights getting poor voltage supply, but I've seen a million reasons why and I'm not really sure how to determine if or why this is.

Third thought is wiring issue, which I hope is not the case and I am unaware of any other lighting issues in the rear. (I currently have Vette Lights Laser LEDs on the rear).

Any thoughts would be greatly appreciated. Thanks.

TL;DR Reverse lights very dim, not sure why. Work as intended otherwise.

 

Dim lights are usually caused by a bad GROUND and not a power issue…all the voltage should be consumed by the load for the lights to be bright.

 

If you are unfamiliar with reading wiring diagrams you have Splice Pack 400 then to C400 (Connector 400) and Splice 402 (S402) then finally to G401 which is at the left rear frame rail which is also the ground for your fuel pump…remove the back up bulb and with a test light connected to battery POSITIVE probe the black wire on the bulb terminal…the test light should be bright if the ground is good…you can find a clean ground in the back and see how bright the bulb should be…use an incandescent 12 volt test light.