Chevrolet Repair Questions? Ask a Mechanic for Answers ASAP
The brake lights have a separate fuse from the high mount brake light.
Have you checked the fuses in the rear fuse block under the back seat?
Do you have power to the 15 amp fuse #34?
It has no power then there is a short in the fuse block. You will need to test for power at that fuse with the brake pressed. If the high mount light is coming on then you know the wire from the brake light switch to the fuse block is good. The best place to start looking is at that fuse since it is essentially the first part of the circuit that you know isn't working.
If you do have power at that fuse then you have a break somewhere between the fuse block and the rear light boards. There should be two light blue wires, one for each side tail light board, coming from the fuse block. You should also see voltage on those wires when the brake is pressed.
Ok. So at this point you'll want to pull the tail light board and check for 12 volts (again, with the brake pressed) at the light blue wire as it goes into the tail light board. You'll need to check both sides.
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