Mechanics

CHEVY BRAKE LIGHTS

2005 Chevrolet Silverado

Electrical problem
2005 Chevy Silverado V8 Two Wheel Drive Automatic 50000 miles

The brake lights on the bed are not working. However the brake light on the cab is working. I replaced the bulbs and I checked the fuses, but that was not it. Please help me figure out what to do?
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JSChevy
April 12, 2009.




First question I always ask is; do you have a trailer connector spliced in behind the bumper? 75% of the time, that's where the problem is. Please advise.

Tiny
James W.
Apr 12, 2009.
I believe I have one but it is factory installed. Does that make a difference? And, what in particular would be the problem there, a short or is there a fuse there?
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Tiny
JSChevy
Apr 13, 2009.
You will want to test your trailer connector to see if you have brake lights there. You're looking for an "open" in the circuit somewhere. The brake light switch has to be functioning or the cab light wouldn't be working.


http://www.2carpros.com/forum/automotive_pictures/248092_brake_lights1_1.jpg



http://www.2carpros.com/forum/automotive_pictures/248092_brake_lights2_1.jpg



http://www.2carpros.com/forum/automotive_pictures/248092_brake_lights3_1.jpg


Tiny
James W.
Apr 13, 2009.
I tested the harnesses that adjoin on the connection block. I get main power coming in. However, when I test the brake connections, no power. I have power to my tail lights, blinkers and all, which look to be coming from that block as well. A parts guy said that usually those blocks go out on one full side, which sounds to me like if it was the block then I would have either the right or the lefts side lights out. You said that it could be an open, but I don't know where to test it to find out, because I am not getting power to my brake lights from that block. What suggestions do you have?

Tiny
JSChevy
Apr 13, 2009.
You're right, the chances of both sides going bad are poor to none.
Let's start from square 1. We'll be testing at the socket for the "turn signal flasher module", under the left side of the dash. The brake lights go through this module.
The brake lights are fused seperately from a 25amp fuse(# unknown) in the underhood fuse block. This fuse should be hot all the time.
Fuse good, yes, test the orange wire at brake light switch.
Orange hot, yes, push the brake pedal and test the white wire on the BL switch.
White hot, yes? Test the white wire at the flasher module, terminal B, with brake pedal pressed.
Hot, yes?, check fuse #9 in fuse block by flasher module.
Fuse good?, yes, check the junctions and connections on the light blue wires going back to the brake light lamps.
Fuse #9 should be hot when the brake pedal is pressed.Let me know what you find.


http://www.2carpros.com/forum/automotive_pictures/248092_05_silverado_flasher_1.jpg


Tiny
James W.
Apr 13, 2009.

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