Wiring

There is probably a cut in the wires. Happened to me. I have to re-connect each and every wire although I only see two wires separated end-to-end. And yes, individually wrap it in electrical wire as having it contact the other exposed wire(s) will cause a fuse to blow or trip the breaker.

The fuses that feed the trailer wiring are usually under the hood of the truck. Look up your truck model and trailer wiring first, but also be sure that none of the wires are touching each other in the worn off piece.

Take the cover off the plug and see if those wire pulled loose from their screws. There’s one wire for left turn/brake and one for right.

Better to replace it. Local RV dealer or Amazon might get it in two days if your Prime.

stickdog wrote:
Better to replace it. Local RV dealer or Amazon might get it in two days if your Prime.

Agreed. Replace the cord. Only if the lights STILL don't work with the new cord would I worry about checking fuses.

stickdog wrote:
Better to replace it. Local RV dealer or Amazon might get it in two days if your Prime.

This harness is what you're looking for.

Bobbo wrote:

stickdog wrote:
Better to replace it. Local RV dealer or Amazon might get it in two days if your Prime.

Agreed. Replace the cord. Only if the lights STILL don't work with the new cord would I worry about checking fuses.

X3. This is the first thing to do and umbilical cords are available at just about any rv dealer.

Here is one way to troubleshoot the issue.

1. Disconnect the trailer plug from the vehicle. If the blinkers and brake lights work on the vehicle, that's good. If not, locate, check, and replace the fuses on the vehicle.
2. Now that the vehicle is working, use a simple test light to test the plug on the vehicle. If you let us know how many pins are in your plug, we can tell you which pins to test. If there is power to the plug, that's good. If not, there may be a second set of fuses on your vehicle for the trailer plug that are blown.
3. Now that the vehicle and the trailer plug on the vehicle are working, replace the wires on the trailer. Wiring kits are available from your local RV dealer, autoparts store, or possible Walmart. The insulation is gone and even though they are taped, they will be nothing but a headache from now on. Water intrusion from rain or puddle splashes could get in and short the wires again.

ndrorder wrote:
Here is one way to troubleshoot the issue.

1. Disconnect the trailer plug from the vehicle. If the blinkers and brake lights work on the vehicle, that's good. If not, locate, check, and replace the fuses on the vehicle.

Lots of vehicles have separate fuses for the tow vehicle's lights and the trailer lights. The tow vehicle lights working properly doesn't tell you anything. You actually need to start with step 2.

ndrorder wrote:
2. Now that the vehicle is working, use a simple test light to test the plug on the vehicle. If you let us know how many pins are in your plug, we can tell you which pins to test. If there is power to the plug, that's good. If not, there may be a second set of fuses on your vehicle for the trailer plug that are blown.

This 4 pin/7 pin trailer light tester will tell you immediately which pins are/are not working. Well worth having in the toolbox for the price. (picture below)

ndrorder wrote:
3. Now that the vehicle and the trailer plug on the vehicle are working, replace the wires on the trailer. Wiring kits are available from your local RV dealer, autoparts store, or possible Walmart. The insulation is gone and even though they are taped, they will be nothing but a headache from now on. Water intrusion from rain or puddle splashes could get in and short the wires again.

This is actually the very first thing you should do.

Here is the picture of the 4 pin/7 pin trailer light tester.