2004 Chevrolet Silverado Brake Fuse Blows

2004 CHEVROLET TRUCK
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DUSTYCOLE12
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i have an 04 chevy silverado z71 and i have put about 5 fuses in the 3rd breaklight location. it blows them after about 5 minutes. i have even put a bigger fuse in it and it still happens. please help me find the problem. thanks
Feb 7, 2006 at 4:38 AM
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VIDEO
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It sounds like you have a short in the wiring harness somewhere. Trace the brake light wires back to the front of the car from the back.
Feb 7, 2006 at 6:09 AM
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DONNELS99
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My suggestion would be to check the light bulb itself. Often the light can ground to causing an overload despite any fuse rating.

Afterall, it is a cheap fix for under a buck.
Feb 8, 2006 at 10:52 AM
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BOLTER_MAN
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Fuse blows when brakes are applied. Replaced brake switch, checked all bulbs and 3rd light, disconnected all and did not solve the problem. Have tried a 30 amp fuse, but when brake is applied, the fuse gets hot. If brake is applied longer than 20 seconds, the fuse blows.
Nov 21, 2020 at 8:30 AM (Merged)
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WRENCHTECH
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That's probably a bad turn signal switch. The 2 lower brake lights pass though it so it can cancel brake lights for turn signals
Nov 21, 2020 at 8:30 AM (Merged)
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BOLTER_MAN
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I unpluged the plug on fire wall that is tail light brake lights and blinkers that go to rear of truck and it did not blow fuse when I applied brake
Nov 21, 2020 at 8:30 AM (Merged)
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WRENCHTECH
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That means you have a short from that point back.
Nov 21, 2020 at 8:30 AM (Merged)
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BOLTER_MAN
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Thanks that is what thought
Nov 21, 2020 at 8:30 AM (Merged)
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MLBKKB
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My truck is blowing the brake light fuse. All bulbs and sockets have been checked. The fuse is for the hazards brake light. The hazards work fine but as soon as the brake pedal is applied the fuse blows. The brake pedal switch has been changed and the problem still is there. This will also blow the fuse when the brake light relay is removed. Any help on this would be very much appreciated.
Nov 21, 2020 at 8:30 AM (Merged)
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PEAR69
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From the brake light switch the wiring goes to the hazzard then turn signal switch. Here is a wiring diagrams so you can see how the system works and a guide to help you test the connections:


https://www.2carpros.com/articles/how-to-check-wiring

Check out the diagrams (below). Please let us know what happens.

Cheers, Ken
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Nov 21, 2020 at 8:30 AM (Merged)
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DLANG51
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I had this problem it was the turn signal switch. It cost me $78.00 for a new one. All fixed! I love this site.
Nov 21, 2020 at 8:30 AM (Merged)
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ANDREWFUELL
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I have the same truck mine keeps blowing the fuse. I even pulled the hazard relay and the turn signal hazard switch and as soon as you hit the pedal it blows the fuse. can't figure it out.
Nov 21, 2020 at 8:30 AM (Merged)
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STEVE W.
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ANDREWFUELL, could you give a bit more information please like the year, engine and if it's one of the higher trim levels? The brake switch feeds more than just the lights, it also goes to the cruise control and the high mounted brake light. A short in those could cause the fuse to blow.
Nov 21, 2020 at 8:30 AM (Merged)
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ANDREWFUELL
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It's a 1996 Chevrolet Silverado 454. but I figured out what happened. I rewired the tail end months ago and there was a white wire in the back loom that I thought was a ground, so I hooked it to a ground and for some reason it wasn't getting a ground until a few days ago and that's when it started blowing the fuse. it was a extra brake wire sent to the back of the truck in the harness. Do you know why they put the extra white brake wire in the loom going to the back of the truck?
Nov 21, 2020 at 8:30 AM (Merged)
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STEVE W.
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Trailer feed most likely. The trucks try to keep them separate so the lighting load doesn't burn up the harness. Thanks for using 2CarPros
Nov 21, 2020 at 8:30 AM (Merged)
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Suggested Repair

Do not install a higher-amp fuse. A short is blowing the brake-light fuse when the pedal is pressed. Inspect the rear harness from the firewall connector back, including the third brake light and sockets, since unplugging that connector stopped the blow. Also check the turn signal switch, which the lower brake lights pass through and which fixed the same symptom for one owner, and verify that bulbs are not shorting to ground and that any extra brake or trailer wire is not grounded.

Conversation Summary

A 2004 Chevrolet Silverado Z71 owner said the third brake-light fuse blew within minutes, even with a larger fuse. Replies pointed to a wiring short, a bulb grounding out, or a bad turn signal switch. Unplugging the rear-light connector at the firewall stopped the fuse from blowing, indicating a short rearward of that point. Another owner fixed the same symptom by replacing the turn signal switch. A later 1996 Silverado case was traced to an extra brake or trailer wire that had been connected to ground.

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