What is causing me to blow the stop lamp fuse in the fusebox under the hood.

SARGE3ID

MEMBER
2000 CHEVROLET SILVERADO
58,000 MILES

I blow the 20 amp fuse for the brake lamp in the fusebox under the hood. The fuse blows when the brake pedal is pressed. It does not blow all the time. I pull a 5th wheel camper and have a trailer connector in the bed of the truck. I have disconnected the trailer connector for the 5th wheel and the one under the bumper. I have the wiring block (for tail lights and tag lights) under the bed of the truck disconnected. I have the trailer brake control disconnected. I have also replaced the brake switch on the brake pedal. The fuse will be ok when I park for the night and blown the next morning. I found that if I crank the engine, w/o pressing the brake pedal first, the fuse does not blow

2 Replies

JACOBANDNICKOLAS

MECHANIC
108,192 POSTS

You have to have a short if it blows over night. Check to see if there is a draw on the circuit with the brake lights off. If there is, it's time to start looking for a short.

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Monday, September 26th, 2011 AT 4:13 AM

CADIEMAN

MECHANIC
3,544 POSTS

Remove the tail light lenses and check the bulbs, sockets and harness. Try installing a fuse. The short is between the brake switch and rear lights. If the rear looks ok. Leave the lenses out and go to the turn signal connecter on the steering column and disconnect it. Try installing a fuse to see if it blows still. Power goes from the brake switch through the turn signal switch then to the rear. There is a short tracing tool that comes with a breaker and gauge.