Troubleshooting Fuse that Blows Only When Making Sharp Left Turn with Trailer

Question:

I have a 2016 fifth wheel 37 foot pulled by 2015 2500 Silverado. Turn signal/brake light fuses continually blow in the truck thereby causing the fifth wheel to not have operational turn signals and brake lights. I have determined the problem is most likely with the fifth wheel since I have no problems when pulling a utility trailer. Heres the odd part: the fuses only blow when making a sharp left turn. The left always blows, the right about 50 of the time. I have physically looked at every wire from front to back with no success. I have pulled, yanked, and twisted every wire including the pigtail in am effort to duplicate the problem, again no success. Any suggestions?

asked by: Darwin S

Expert Reply:

The fact that the fuses in your truck are blowing only when making a sharp left turn leads me think there are a couple possible issues that are causing this.

The first thing I recommend checking is the length of wire you have, specifically where the trailer and vehicle connectors attach to each other. I am wondering if it isn't quite long enough between your Silverado and trailer and when you make a sharp left turn, it is causing some wires to pull or the connector to twist a bit, leading to a short. I recommend having a buddy observe outside the vehicle while you make a slow, sharp left turn so he can see if this is happening and if a longer harness might be in order.

Also check again to make sure all of your trailer wiring is in good condition, free of any damaged or frayed sections. It could be that there is an exposed piece of wiring that might come in contact with the trailer frame (or another exposed wire) when making a sharp left turn.

Lastly, just check that all your ground connections are made to clean, bare metal surfaces and that the vehicle and trailer side connectors are free of any dirt or corrosion. This can also lead to a short.

If you are unable to resolve the issue, please let me know and I will be happy to look into this further.

expert reply by: Chris R