Troubleshooting Vehicle Wiring Harness # 41165 Installation on a 2006 Chevrolet Colorado

Updated 02/22/2010 | Published 02/21/2010

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Hopkins Plug-In Simple Vehicle Wiring Harness with 4-Pole Flat Trailer Connector

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$42.16

Question:

I bought the the 41165 kit and installed it. When I plug into the trailer I only have brake lights that work correctly on the trailer. When you turn on turn signal all trailer lights flash and there is not any taillights when the lights are turned on.

asked by: Jerry W

Expert Reply:

To isolate where the problem is occurring, I recommend testing the 4-Way plug on the # 41165 wiring harness with a circuit tester, without the trailer connected.

Have someone assist you by engaging the tail lights, pressing the brake pedal, and flipping on the turn signals as you test each corresponding port on the plug. You should only see a flashing current on the yellow (left turn) and green (right turn) ports when the turn signals are activated.

If the functions are reading correctly at the plug, the issue will most likely be on the trailer side. From the lighting behavior you are describing, it sounds like you may have a bad ground in the trailer wiring system. Check to make sure the ground wire from the trailer connector is firmly connected to a clean piece of metal on the trailer frame.

If you find that the ground from the trailer connector is connected correctly, check along the rest of the wiring to make sure there are no pinched or bare spots that could be causing a false ground.

If your trailer lights are grounded through the light hardware, make sure that the all connections between the light, light bracket, and trailer frame are free from corrosion, and that they are still firmly attached.

expert reply by: Robert G