Troubleshooting Vehicle Fuses Blowing When Trailer Coupler Connects to Hitch Ball
Question:
My running lights on trailer works fine but second I connect to the ball hitch it blows the running and tail light fuse on truck. Any idea of what’s causing this?
asked by: Jackson
Expert Reply:
It sounds like there is a short somewhere in the wiring. First, make sure that both the vehicle side and trailer side connectors are free of dirt and corrosion. If the connector is corroded or dirty, it can cause excess power draw and blow a fuse. Simply clean out as needed.
To start testing on the vehicle, you will want the change all of the blown fuses and then using a circuit tester like # PTW2993, test the vehicle side connector. You'll need some help so someone in the vehicle can run through the functions while you test each pin on the connector. If you detect any power to a circuit when there should not be any, then you know there is a short somewhere on the vehicle side. Simply trace the wiring back from the plug and look for any exposed areas that might be touching bare metal. If the vehicle harness is damaged, you can also replace it using the Curt # C55379, which is a plug and play harness that's easy to install.
If everything checks out fine on the vehicle side, then you will want to check along the wiring for the trailer, again looking for any damaged or exposed wiring that might be touching a metal surface. You can also test the trailer wiring for function by connecting each wire to a 12V battery. Lastly, make sure that the main trailer connector ground and all the light grounds are securely attached to clean bare metal surfaces.
If you are unable to find the issue, please let me know and I will be happy to look into this further.
Products Referenced in This Question
Curt T-Connector Vehicle Wiring Harness with 4-Pole Flat Trailer Connector
- Custom Fit Vehicle Wiring
- Trailer Hitch Wiring
- Converter
- Custom Fit
- 4 Flat
- CURT
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