Electric Trailer Jack Blows Fuse

Question:

Hello, I found the post Troubleshooting an Electric Jack that keeps Blowing Fuses and was helpful. Was wondering if there was a follow up to this? I have a very similar situation with my FIC-3500 electric jack. When raising or lowering the jack with weight, the fuse blows and after a few seconds it starts up again. The resetting fuse must be working, but the fuse keeps blowing every inch or so. Once the weight is off the jack, the fuse no longer blows. All wiring looks good. Is this a switch, fuse, or mechanical problem? Thanks

asked by: Aaron L

Expert Reply:

This is typically caused by an insufficient ground connection. The jack grounds by its physical connection to the trailer A-frame, but if the paint on the frame is thicker than usual and/or the powder coating on the jack mounting flange was applied too thick, it'll prevent a good ground connection. I'd remove the jack, sand down a dime sized hole around the mounting holes on the trailer tongue and on the underside of the mounting flange. Use some star washers around the mounting bolts so they are sandwiched between the mounting flange and the trailer A-frame. The washers will get a good bite into the metal, and ensure good contact for a reliable ground connection.

You'll also want to ensure that the jack is receiving a full 12-volts and that the actual tongue weight of the trailer isn't exceeding the capacity of the jack. Take a look at the circuit powering the jack again, and make sure there's no worn spots in the wire insulation, which can occur at the point where a wire passes through a hole.

expert reply by: Mike L