Brake light issues...help please.

[One1999Chev]

I noticed that my brake lights were not working when I had turned on my headlight switch. However whenever I pressed the brake pedal all of the brakes lit right up. This is a recent thing as before they all worked how they should. Any ideas where to start?

I checked all the fuses tonight and I did not find any blown ones, I also tried cleaning up the tail light ground near the back of the truck, but after I did that my signal lights are now extremely fast!

The truck had LED park lights when I got it but I took the front clip off and reconnected those recently (is it possible I plugged them in wrong and caused problems?)
I also just got a new LED 3rd brake light from Anzo and again it seemed to work when I pressed my brake pedal but it does not come on when I try the cargo lamp switch.

I am stumped as I thought for sure it was going to be a fuse, but they are all fine, and it seems like anything I touch something else is going wrong!!

 

[east302]

Do your license plate lamps work?


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[DerekTheGreat]

Pull the taillights and then take off the 7mm? bolts that hold the circuit board to the taillight housing. If that board is all corroded the bulbs wont chooch. Sometimes it's so bad even the harness gets all corroded. Our '89 and '88 trucks had those issues only worse- reverse lights wouldn't work and the brake light one side didn't either. I swapped in boards that were in better shape and presto, chooching lights again.

 

[88Scottsdale]

It may also be worth making sure the ground for the rear lights is still tight and snug to the frame. Had to take my bed off to change rusted brake lines over the weekend and forgot to re-ground the rear lights to the bed frame and had a similar experience to you.

Good luck.

 

[Bob L]

Need to do some diagnosing with a test light. If you have power to properly grounded test light then your lights have a ground issue. If you have no power then you have to find out where it comes from and check that end. The cargo light and third brake light are to separate circuits. The cargo light doesn't light with brake only and the brake light doesn't light with the cargo lamp on only.

 

[One1999Chev]

License plate lights are NOT working.

I tried to clean the ground on the back of the truck last night and after that is when my signals started going super speed....must not have reground well enough.

I will be starting there again soon and trying to get that grounded up well. Will keep updated.

I may also try switching the entire headlight switch panel from my '96 to this truck to see if that may be the issue that the brake lights won't come on when I have the headlights turned on.

I highly doubt it will be my circuit boards as they are brand new and have all LEDs in them, but I will check them out since its pretty simple. It's not the the bulbs won't "chooch", it's that they do not turn on when I have my other lights on. They work fine when I press the brake pedal or even reverse.

 

[One1999Chev]

So after I cleaned up the ground for a 2nd time and retightened it up I noticed the lines running through the frame and into the plug (that has all the wires to the back end basically) were all stitched together and covered with ****** red duct tape or some low quality red electrical tape of some sort.

Anyhow, pulled all the tape off and sure enough 4 out of 4 wires had been cut or broken at some point and 1 was basically completely unhooked. I cleaned up both ends and used some pinch connectors to hold the wires together better than they had been.
Problem solved. My brake lights now work when my headlight switch is turned on, as they should.

 

[One1999Chev]

But the original problem I was looking for is still unsolved.
I am glad I found all this to fix it though since it was unknown to me.

I bought a new LED 3rd brake light from Anzo and I can't seem to get the "cargo" light to come on at all. My cargo lamp switch is on, I have turned the interior dial to the max, but it still isn't working.
Do some LED lights just not have the capability for anything but being brake lights?

 

[east302]

Here are the diagnostics for the cargo lamp, hope it helps.

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[One1999Chev]

thnx, ill try diagnosing the wires...Guess I will have to pull the dash though?