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Svrforst 12/28/2017

2010 GMC Sierra 1500 SLT 8 Cyl 5.30L


No high beam, taillights, window washer

Within last few days my high beams, taillights, and window washer stopped working. Cant find any bad fuses, relays SEEM to be good(switched with others). Everything else appears to be working as normal. Completely lost on what is causing this.

1 Answer


HouseCallAuto 12/28/2017

These 3 circuits are unrelated to each other. If I were there and had to find the cause, the first thing is confirm that there is no 12 volt signal going to the high beam headlight bulb. Remove the bulb from the rear of the headlamp and just access the wires. For example, the right high beam connector has a light green / black wire (or it could be orange) and when you turn the high beams on this wire should illuminate a 12 volt test light if you simply had two defective headlamp bulbs which is not likely - confirm that it DOES NOT and then proceed with the rest of what I am putting here.

If you have no 12 volts going to the high beam bulb connector along with no windshield washers and no tail lights, then it is a greater than 90% probability that you have a defective underhood fuse box on the left side under the hood, or upon disassembly of this fuse box from its mounting you may find some wires under the fuse box eaten through by a rodent. The only thing these 3 different circuits have in common is that all three have wires that go into this fuse panel, and all 3 circuits use relays of which at least 2 maybe all 3 are directly soldered to the fusebox printed circuit board. It is not uncommon for fusebox failures like this, and its always different symptoms.


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