First off, I have tried searching/reading plenty of threads with no help to my problem. I have a 95 3.0 4x4 'ext cab' 5 speed manual trans and when I shift the truck into reverse with the headlights/parking lights off, I notice that my parking lights come on along with the dash cluster lights. It would seem to me that the reverse lights 'should' be their own circuit, but apparently not and for whatever reason are tied in (somehow) to the dash and parking/running lights(??)
I hear people say in many threads that have to do with any electrical issue to "check the grounds" but I was hoping that someone could expand a little on that. Where are the common ground locations located that usually need attention? Anyone have any idea why my reverse lights somehow can backfeed to the other lights mentioned?

 

Do you have a aftermarket trailer light harness or homemade adapter. Sounds like the reverse lights might be spliced into your parking lights.

 

It could also be in or around the tail lights themselves. I haven't been around the back of a pickup so I don't know where the ground wires are for the lights, but they will have a wire that connects to the frame. If it isn't connected the reverse lights will feed through another circuit to find ground, just like you're describing.

Has any recent work been done anywhere on this vehicle? Bulbs replaced or anything? Pinched wires can also do this.

 

Thanks guys for the replies. I recently bought this truck in Dec. so I haven't touched anything on the wiring. It does have a seriously crappy harness 'spliced' in. It is pretty cold here yet to work out in a muddy driveway though. I will try and eliminate it(harness) when the weather allows and see if that corrects things. This problem just started about a week ago though, so it seems as if the harness was added 'correctly' at first when I bought it. I'll have to trace all the wiring for sure.

 

a similar issue occurred not too long ago with someone else. yeah, if removing the harness doesn't do it, you'll have to trace all wires. these problems have been known to get hot and short if spliced. galvanic corrosion > increased resistance > heat > short

https://www.yotatech.com/forums/f2/w...g-bald-230788/

 

i had a issue where the wires for the rear lights passed threw into the back of the bed behind the tail light the wires had been rubbing on the body and wore threw the insulation on a couple wires.

 

That seems to be what I am hoping for and maybe it can be corrected easily.
I would hope it is isolated to a problem towards the rear of the truck. I have heard mention of ~possibly~ the headlight switch, but I seriously hope not. I'm sure those aren't cheap(?) and difficult to change(?).

My logical guess would be the reverse power somehow crossing with parking(running) lights since the reverse lights can 'power' the parking/dash lights with the parking/headlight switch in the off position. It seems the reverse lights 'trump' the lighting system now somehow.

 

Just to help this not be yet another dead end thread without a fix, I do believe the added in trailor wire harness was my problem. I removed it and all seems correct although all the wiring was correct. The 'octopus' board that was part of the aftermarket wire harness seemed to fail internally.

 

I only suspected it because it happened on my truck.