Hello, I'm Aran. I will assist you with your Chevy issue and see to it that you have a positive experience. Your COMPLETE satisfaction is my goal.I am uploading a diagram to reference starting at the light green highlight, that is the stoplamp switch. If you follow the red arrows the circuit has to be good all the way over the the fuse called VEH CHMSL as the 3rd brake light works.So the first step is to back step to the fuse called VEH STOP and check that fuse for power with the brake pedal depressed for power. If it has power then jump to the rear of the vehicle at the junction block rear lamps and check connector C1 TERMINAL B for power with the brake pedal depressed.If you have power there, the issue is after the junction block, I have had a few bad junction blocks. You could further verify the issue by unplugging connectors C1, C2 AND C4 and then using a small jumper wire from C1 TERMINAL B to either C4 TERMINAL A or C2 terminal D and if each corresponding brake light comes on then yes the rear junction block for the lamps is bad on that circuit.If you do not have power to the rear light junction block then there is an open in that circuit between the rear light junction block and the fuse block on the left side of the dash or the FUSE BLOCK I/P.
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Thanks for the assist. It is 1224 in the morning here in Hawaii right now. I will tackle this in the morning and let you know what I find out.
Not yet. I am replacing the junction block today. Hopefully that will fix it. I went to a salvage yard this morning a het one and it didn't fix the problem. My wife is going to the dealership right now to get a new one. The dealer parts guy said he thinks it is the blinker switch thing under the air bag. Could that be true?
I put the millimeter on the setting to check for continuity and put one prong on each side of the fuse port. I had continuity when the break was not pressed but when I pushed the break there was nothing. Do I need to check it in a different way?
I ran a wire from the neg post on the battery for ground and put the red prong from the millimeter to the fuse and have power when the break is pressed.