No Power on the Left Turn and Brake Light 7-Way Trailer Connector Pin on a 2007 Chevy Tahoe

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Pollak Heavy-Duty, 7-Pole, Round Pin, Trailer Wiring Connector - Trailer End

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Replacement Custom Multi-Tow 7-Way and 4-Way Trailer Connectors

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$38.03

Hook Probe Circuit Tester

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Question:

The yellow wire left turn signal and brake light on the factory wire harness does not receive a signal current for either the turn function or the brake function. I assume that there is a problem or break in that wire as all other functions work. I spliced into the yellow wire going to the left tail light and now the left turn light on the trailer will work but the left stop light on the trailer will not work. Is there another wire going to the left tail light that I need to spice into and connect to the factory plug? I do not understand why one wire yellow to the socket controls both stop and turn but two wires control stop and turn in the tail light assembly? Help! How do I get the left brake light on the trailer to work?

asked by: John

Expert Reply:

The problem is that on your 2007 Chevy Tahoe, the turn signals on the vehicle are on a separate circuit than the brake lights. Trailers use a combined stop and turn circuit. When trailer wiring is added to a vehicle, vehicles with separate turn and brake lights get those signals converted to a single function by a converter whether from the factory or aftermarket.

If yours is from the factory, it sounds like something has gone wrong, but I can tell you what to look for. First, take a look in the vehicle owner's manual for all the fuses and relays related to the tow package wiring. Check to see if any are blown or bad and replace as needed. Connect the trailer and see if that solves the issue.

If it does not, then there could be something wrong with the connector at the back or anywhere along the wiring from the front to the back. First try cleaning out the trailer and vehicle side connectors. Corrosion can build up causing a poor connection and it can build up where the wires attach as well. You can try replacing the connector using # 30955. Test the wiring behind the factory plug a ways to determine if the wiring is carrying a signal to that point. You can use a circuit tester like # PTW2993 if needed.

Splicing directly into a brake light wire from the vehicle will not work because it can backfeed into the turn signal on the vehicle and damage the electrical system.

expert reply by: Michael H