Troubleshooting Pop-Up Camper Trailer with Non-Functioning Lights

Question:

We have a new 7 RV blade connector on our SUV and our newly purchased, but quite used pop up camper does not project any lights running, signal, brake, etc. lights when plugged up correctly. From the bit of wiring we can see, there does not appear to be any corrosion or fraying on the wires, but we know most of the wiring is hidden. We do not have the equipment or experience necessary to do the testing. What might the problem be, and where can we take it to have it tested and troubleshoot the issue? We are novices.

asked by: S. T

Expert Reply:

Since you are now dealing with troubleshooting trailer wiring you are no longer a novice!

The best way to go is to isolate the problem to either the vehicle or the trailer. If no lights at all work on the trailer, then this makes me suspect the vehicle wiring is not activated. Some vehicles may need fuses or relays installed to activate factory or aftermarket wiring.

Without knowing your vehicle details the best suggestion I can make is to get a circuit tester like # PTW2993 and apply it to the various contacts inside the 7-way socket while a helper activates each light function (one at a time, of course) so you can test the appropriate contact pin to check for the signal that should be there. The linked video illustrates use of the tester, and the linked photo of a 7-way shows you which functions are carried on each pin so you'll know where you need to test for each function. Ground the tester to the ground pin and then test each circuit individually.

You can also test the pop-up camper without any special equipment. All you need is a well-charged 12V battery like the one in your vehicle. Apply the positive and negative battery connections to the trailer's plug, one circuit at a time as you did with the circuit tester on the vehicle. If you have a dead lighting circuit when the trailer is getting directly powered in this way, then you may have damaged wiring somewhere between the trailer plug and the lights themselves.

Sometimes corrosion can build up inside a trailer's 7-way plug. It may be tough to see from the outside but can still cause issues inside the connector, such as a dead short. If this is the case, then you may need to install a new 7-way. We have kits like # HS381-9000 which includes both a new 7-way plug and wiring junction box that lets you make the connections from the existing trailer wiring.

Please tell me the results of your initial testing and I will be glad to work with you further to find the solution.