Trailer Turn Signals Not Working with # C55050 Wiring Harness Installed on a 2008 Jeep Commander  

Question:

Expert Reply:

It sounds like you have one of two problems. First, I would check the wiring harness at the back of the vehicle. Disconnect the trailer and make sure the ground wire is connected to a clean, rust, paint and corrosion free ground location. Then using a circuit tester, item # PTW2993 if needed, test the wires going into the converter.

The red wire should have the brake signal on it, the green wire should have the right turn signal on it, the yellow wire should have the left turn signal on it, and the brown wire should have the taillight signal on it. If all of the functions going into the converter are correct, then the connections at the rear of the taillights are correct and you will need to test the signals coming out of the converter.

The white wire coming out of the converter is the ground wire, the yellow wire will have the left turn and brake signal on it and the green wire will have the right turn and brake signal. The brown wire will have the tail light signal on it. If all of these functions are correct and test out with the brakes applied an the turn signals activated, with no trailer, then the vehicle side is correct and you will need to turn your attention to the trailer.

If the trailer is the problem, it is most likely a ground issue. You will need to check each light and its ground location and the ground at the trailer tongue. While checking the ground locations keep an eye out for a frayed, pinched or otherwise shorted out wire in the trailer wiring. Make sure to check the lights connection to the trailer frame if there is no separate ground wire on the lights.

With a little bit of investigation we will get to the bottom of the problem.

expert reply by: Robert G

0

George

8/25/2010

Plugged in the pigtail and this is what i have running lights work left blinker and right blinker works with blinkers off brakes work when i turn blinker on and then brake the blinker stops and all i have is brake take the brake off and the blinker works does this on both sides.

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Bob G.

8/25/2010

From all of the information you have provided it really does sound like a ground issue on the trailer. Many times, on pop-up style trailers, the ground wires for the tail lights are attached to sheet metal and, over time, the ground connection is deteriorated due to corrosion. I would remove the rear tail lights and connect a lengthened ground wire to each light and route it through the trailer down to the trailer frame itself. Using 12 gauge wire should be sufficient. If there are any other lights on the trailer you may need to make sure they are grounded to the trailer frame also. Be sure to connect the new ground wire to a clean paint, rust an corrosion free spot on the trailer frame and to avoid any areas that could pinch fray or cut the wire. When a ground is deteriorated the power will try to find its way to ground in any way possible, that is why the functions on the trailer seem to be working one way and then change after checking things.

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George

8/25/2010

I plugged the pigtail into the back of the jeep , i did not have it connected to the trailer at all.

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Bob G.

8/25/2010

If the trailer wiring harness is not working on the Jeep then you will need to test the wires going into the converter. If the wires going into the converter are all carrying the proper signals, then the converter has been shorted in some way and will need to be replaced. If the wires going into the converter do not have the correct signals then it is possible that one of the pins in the converters connector is bent causing the issues you are having. You would need to disconnect the connection points at the rear tail lights and check the insides of the connectors to be sure nothing is bent. If this does not solve the issue I would recommend replacing the converter. There is one other thing that could be causing a problem like this. I dismissed it before because the 2008 Commander does not come with LED tail lights, but if you have added LED tail lights, on the Commander not the trailer, then that could be the reason that the converter is not working. In this case you would need to hard wire a powered converter to the tail light wiring, using a circuit tester, item # 3808 if needed, to determine the right turn, left turn, brake and tail light signal. Using the # 118408 wiring harness you will need to connect the green wire to the White wire to a solid clean ground, the smaller red wire to the brake light wire found on the vehicle, the yellow wire to the left turn wire found on the vehicle, the green wire to the right turn wire found on the vehicle and the brown wire to the tail light wire found on the vehicle. The larger red wire is ran to the vehicle battery through a inline fuse, included in the # 118408. Remove the fuse before connecting the power wire and when you are sure the installation is complete replace the fuse. Using a powered converter will power the trailer lighting from the vehicle battery. The converter will only draw a small amount of power, .5 milliamps, from the vehicles tail light wiring and this will allow the trailer lighting to work with the LED lights. A powered converter also protects itself and the vehicle from any type of short circuit situation on the trailer.

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