No rear lights ... 3rd brake light does work

[bugdewde]

1995 Suburban 2500

Refresh my memory, please.
I searched and found a few related issues, but I'm still confused..... lol.
Most posts mention :
1. brake light switch
2. tail light circuit boards
3. hazard switch
4. turn signal stalk.

Any help on my situation?
- 3rd brake light DOES work.... it operates.
- Absolutely no lights in the housings, including reverse lights ....No lights work at all in the housings.

 

[bugdewde]

Add to the post ..... my trailer brakes work as well as the 3rd brake light. So assuming brake switch is good.

 

[GoToGuy]

Trailer brake lights? Do turn signals work on truck and or trailer since you added it? High mount brake light is powered before brake light power enters steering colum through turn signal multifunction control. Did you check for power at rear tail, brake since trailer works. Did you check ground at rear frame for tail brake. Tapped into rear wires for trailer lights? Truck lights power but no ground no workie.

 

[Dylan Burow]

I would check for power at the rear taillight pigtail. Should be a weatherpak under the bimper kinda by the end of the frame rail. Do they stay out or do they go back on over bumps?

 

[Dylan Burow]

I would also check the ground for the rear lights if you live in salt areas they are notorious for rusting and becoming disconnected. That should be in a similar location on the opposite site of the bumper on the frame rail

 

[PlayingWithTBI]

There was a similar thread about this and it turned out to be a bad ground from the passenger's side head to the fire wall, IIRC.

 

[bc-chris]

I would check for power at the rear taillight pigtail. Should be a weatherpak under the bimper kinda by the end of the frame rail. Do they stay out or do they go back on over bumps?

^^this!! i had my truck in the shop one time and they forgot to plug the rear pigtail in before giving it back to me. i was not impressed.

 

[bugdewde]

Trailer brake lights? Do turn signals work on truck and or trailer since you added it? High mount brake light is powered before brake light power enters steering colum through turn signal multifunction control. Did you check for power at rear tail, brake since trailer works. Did you check ground at rear frame for tail brake. Tapped into rear wires for trailer lights? Truck lights power but no ground no workie.

Trailer lights do NOT work either. Tails, brake nor blinkers. However, the trailer brakes work (actual brakes, not the lights).
Unhooking the trailer pigtail does not fix anything. Hooking up to another trailer does not fix anything. Both trailer's lights work when hooked to another vehicle (my Jeep). So I'm ruling out the trailers.
Today (Sun) I'll be able to investigate more. Checking grounds, connections, etc.
Was just hoping to find a quick, definitive answer since this appears to be a common occurrence. Several years back, my '99 6.5 'Burb did the same thing (3rd brake light worked). I replaced the brake pedal switch and all was good. A few months later, there was another issue and I had to replace the hazard switch.
Hoping to not have to mess with the turn signal stalk on this one. Lol.
Since the reverse lights quit working as well, I was hoping it would be a quick diagnosis from you guys (maybe housing circuit boards) and I'd be ahead of the game.
I'll get to poking around today and see what's up.
Thanks!

 

[bugdewde]

Understanding the flow of power tjrough the switches would help.

- So you're saying the 3rd brake light powers BEFORE the steering column?
So the switch on the pedal should be good, as the 3rd brake light works?
- Leaving the hazard switch and the turn signal switch the next possible candidates to look at?
------ ------ ------
Do the reverse lights power also go through the hazard and turn signal switches? Since my reverse lights do not work either, was hoping the issue is related to the housings only (or rear wiring). Just wasn't sure if the reverse lights are also powered through the hazard and turn signal switches.

 

[bugdewde]

Thanks guys .... I found the issue. Much ado about nothing! Lol.....
Was able to see it right off thanks to you guys.
The harness behind the bumper came disconnected. Looks like the trailer wiring harness. Seems the retainer tab is broken. Zip tie to the rescue.