98 Chevy Z71 Brake Lights Dont Work

[kewltexan]

Just found out my brake lights dont work on the right and left of the tail gate.
The brake light on top of the cab does work.
The bulbs all work (replaced anyway). They work as running lights, turn, reverse, hazard but not brakes.
No blown fuses.
I even replaced the circuit board plates behind the lenses with no luck. (I found one bulb socket that looked corroded and burnt so I replaced both sides)
I dont think it's the brake light switch because the top cab brake light works.

Anyone got any ideas?

Thanks

[2000CAYukon]

Originally Posted by kewltexan

Just found out my brake lights dont work on the right and left of the tail gate.
The brake light on top of the cab does work.
The bulbs all work (replaced anyway). They work as running lights, turn, reverse, hazard but not brakes.
No blown fuses.
I even replaced the circuit board plates behind the lenses with no luck. (I found one bulb socket that looked corroded and burnt so I replaced both sides)
I dont think it's the brake light switch because the top cab brake light works.

Anyone got any ideas?

Thanks

Check the ground for the brake lights.

//2000CAYukon

[777stickman]

Welcome to the forum and compliments on a great post.

Your input on the 3rd brake light indicates the stop switch is not the culprit.

In the "Underhood Fuse Block" there is a Stop lamp relay and a 30a maxi fuse (fuse #2). The relay gets its signal from the stop sw and the brake lights are powered thru the relay from the "maxi fuse".

I don't think the ground at the tail lights is the problem (sorry YUKON) since the turn signals are working and the brake lights use the same bulb and filament.

Also in the wiring to the left & right brake lights is the turn signal switch. Even though the turn signals work the left & right brake light signal goes thru that switch.

Lots of things to look at. Post back if you have more ?'s.

[ironheadracing13]

It could be your mulity function switch. Try wigling your turn signal and hazzard switch.

[kewltexan]

Thanks 777stickman!!!!!!!!!!!

You Rock.

The culprit was the brake light relay in the fuse box under the hood.
I took it out and there was a little rattle in it.
It took a few hours to find one. I should have just gone to a Napa store to begin with.
Brake lights work now.
Quite a learning experience. I never thought there was such an elaborate scheme to what makes those brake lights come on.

Many Many Thanks

[777stickman]

You are very welcome and thanks for posting back the fix.