Troubleshooting Right Turn Light on 2002 Pop-Up Camper Trailer

Question:

please give me some Idea what I can do to repair this problem,or how to trouble shoot.

asked by: Francis F

Expert Reply:

First thing, disconnect the trailer from the tow vehicle wiring and use your vehicle battery (or a well-charged spare 12V battery) to apply power directly to the pin for the right-hand turn signal; on 4-pole wiring this is a green wire. This same green wire also carries the right-hand brake light signal. Please refer to the linked article on trailer wiring to see all connector types and which pin handles the right turn signal.

If your direct application of battery power does not cause the light to illuminate then check for a blown bulb and check the socket for discoloration/corrosion. If they are OK then move upstream along the wiring, forward to the trailer connector, looking for signs of damaged wires or worn insulation. Also inspect the trailer plug's contact for discoloration/corrosion. Even a slight greenish or whitish film can indicate a corrosion problem.

Among the most common causes for a trailer light to stop working is a bad ground. Some lights use a separate wire to make the ground connection while others might use the light's mounting post, that contacts the trailer's frame, to establish the ground. Either way, if corrosion or dirt has built up in that area it can interfere with the ground. Check the problem light's ground wire or stud, as the case may be, to ensure it is solidly attached to a clean bare metal surface. You might need to sand off the grounding point to give you a clean bare metal surface.

If you do find that there was corrosion you can apply dielectric grease like # 11755 to the grounding point to prevent future corrosion. You can also apply the grease to the bulb base and socket to protect them.

If the trailer light works with this direct power, then you know the issue is on the vehicle side. In that case use a tester like # PTW2993 to check your vehicle wiring harness to see if it is delivering the signals to the connector. Have a helper turn on the right turn signal and test the pin for the green wire on the vehicle harness to see if signals are there. If not, then you may need to replace the wiring harness.

Please tell me the results of your troubleshooting and tell me about your vehicle and I will be glad to help further.