2000 Silverado Brake Light Issue

[scwidy]

Hello all, I have a question that hopefully someone has the answer to. I have a 2000 silverado z71 and recently was told my rear brake lights were out. Well, I checked they are but the third brake light on the cab is working and the trailer plug at the hitch lights up when the pedal is depressed. I have checked the bulbs in the taillights and they are good and the fuses in the engine bay and in the cab are good as well. Any suggestions?

[c4cruiser]

I would suspect the brake light switch at the pedal. The 3rd brake light usually has its own wire and a separate connector on the switch. Not sure if the trailer brake lights come off the truck brake lights wiring harness at the rear of the truck, but I would think they are on a separate circuit and a separate wire on the connector at the switch.

[ChevyTech77]

Turn signal or multi-function switch. Unless the trailer connector is pulling the brake light bulbs down because if

an internal short in it's connector or the plug itself. Seen that a bunch too. Check for power at the bulkhead connector under the rear of the truck bed by the spare tire. If you have power there, it's somewhere in the back

of the truck. Try them with the trailer plug disconnected too.

 

If the brake light switch was out, so would be the third brake light.

[Duelin]

Check the tail lamp circuit board. They are known for shorting out.

[scwidy]

Thanks all for your help, I ended up replacing the circuit board behind the spare tire and my lights lite up!