I love it when folks post these kind of questions..........

[alpinecrick]

.......now it's my turn in the barrel.

Not sure if this is the correct subforum for this question.

'96 K1500 ECSB:

No brake lights, no third light either. Every other light works fine.

Having owned/own 4 GMT400's I'm familiar with the usual suspects--I've replaced the brake light switch, fuse in the cab, fuse under the hood and the relay. Brake lights still ain't working.

Because the third light isn't working it leads me to believe the problem is up front rather than the harness in the rear.

For a start, can anybody tell me what color is the hot wire going into the brake light switch? And what wire is hot when the switch is activated going OUT of the switch to the brake lights? Seeing as how space is so limited under there a guy can only put one eyeball at a time on the switch and harness.....

Thanks in advance for any help, suggestions and experiences.

 

[Hipster]

A gallon of gas sprinkled around generously and a match is the quickest way to get it hot unless I'm misunderstanding you. lol

 

[df2x4]

I'd still check the trailer wiring harness under the bed. Easy to check and one of the most common failures I read about on these when it comes to light issues.

 

[alpinecrick]

I'd still check the trailer wiring harness under the bed. Easy to check and one of the most common failures I read about on these when it comes to light issues.

No power to the brakes lights at the harness either. No brake light on the third light points away from the harness in the rear.

 

[LS6rally]

Brake light switch on the pedal?

 

[Mr.White98]

This link is floating around here somewhere, I can't remember where since I bookmarked it.

http://www.diakom.ru/CAR/GMC/1997/Pickup K1500/SYSTEM WIRING DIAGRAMS/

Check out the Exterior Lamps Circuit for the brake lights. If you have access to a DMM, trace the circuit to where you lose power. Having a 6.5 diesel, I know that grounds are very important, something worth looking into on the relay. Good luck

 

[alpinecrick]

This link is floating around here somewhere, I can't remember where since I bookmarked it.

http://www.diakom.ru/CAR/GMC/1997/Pickup K1500/SYSTEM WIRING DIAGRAMS/

Check out the Exterior Lamps Circuit for the brake lights. If you have access to a DMM, trace the circuit to where you lose power. Having a 6.5 diesel, I know that grounds are very important, something worth looking into on the relay. Good luck

Thanks Mr.White! Those files might make it easier.

I'm beginning to think it's my turn signal switch assembly.

 

[alpinecrick]

Brake light switch on the pedal?

New brake switch. No power at rear harness anywhere for brake lights or cab mounted brake light, all other lights work.

But, my hazard flasher button on the steering column won't pop up, it's locked into off position. I have no "key in ignition" alarm or "lights on" alarm either.

 

[CrustyJunker]

New brake switch. No power at rear harness anywhere for brake lights or cab mounted brake light, all other lights work.

But, my hazard flasher button on the steering column won't pop up, it's locked into off position. I have no "key in ignition" alarm or "lights on" alarm either.

Do the turn signals work? Also do you know if your tail lights worked before the hazard button jammed? I haven't had this exact problem, so forgive me for Internet-troubleshooting.

 

[Lowco8]

check yours grounds. they rust easily. Also if your did any recent work you may have pinched or put a stray screw through a wire.