Hi Bruce,
Let's back up for a second. Are you wired like this?
http://www.countrytrailer.com/uploads/7wayplug.pdf
Using an inexpensive 12 V test light / tester like the one below, connect the clip to a good ground on the vehicle. Then with someone else working
the brakes, turn signals, lights, etc. ONE AT A TIME, you should push the point end of the tester into the corresponding connection on the VEHICLE. Only one connection should have power at any given time. Once you have verified that the correct & only connection has power at the right time - you can move to the trailer end of the wiring. If you can not verify the vehicle plug is working correctly - you'll have to get it working right before continuing. These connectors can develop problems over time and may need servicing.
If the trailer still has issues, check ground by uncoupling the trailer hitch from the ball on the vehicle. Keep the 7 pin connector from the trailer plugged into the vehicle and turn on the vehicle lights / have an assistant step on the brake. Connect the clip to the frame of the trailer and push the point to a good ground location on the vehicle. If the tester lights up - you have a bad ground wire between the vehicle wiring to the jack and the trailer frame somewhere. The lighting is relying on the contact between the ball & hitch for ground and could be causing the problem.
Check all the bulbs to make sure that they are the right ones and if the offset bayonet base type - inserted properly. Inspect lamp sockets, wiring and ground leads at each lamp socket. You can also disconnect a wire from a point that is common to left and right sides of the trailer to help narrow down where to look on the trailer for the trouble. If you disconnect a wire going to the left side and everything on the right works as expected when trying all the lights, brakes, etc. then you know the problem is probably on the left side. Reconnect the left side and disconnect the right side and test again. It is a process of elimination when you can't see anything obvious. Keep disconnecting 1/2 of the side that is causing trouble until you find the problem.
You can purchase a 7 wire vehicle jack test plug like this to quickly diagnose the vehicle for less than $10. It will indicate on the LEDs the power seen from the vehicle.
×