2004 Expedition fuse 42 for trailer lights keeps blowing. Please help.

[Stotzbotz]

Hello and thanks for attempting to help as I'm trying to help a friend who owns a nice 2004 Expedition. Whenever he has his trailer hooked up electrically, fuse 42 keeps blowing that supplies voltage to the driver's side trailer lights. The same trailer was checked out and used with other vehicles and worked fine not causing any trouble. It's only a 10 amp fuse so I'm wondering if a 20 amp might be better as this fuse monitors the voltage to the brake and turn signal to the drivers side. The lights work for a little while then when you go to hook the trailer back up again it doesn't work due to the blown fuse. Wondering if anyone has seen this before and has any suggestions. Any help would be greatly appreciated.

 

[Calidad]

If the trailer isn’t shorting other vehicles? Then the truck plug likely has a short. When the trailer is plugged in it’s causing the plug on the truck side to short.

 

[Fastcar]

Hello and thanks for attempting to help as I'm trying to help a friend who owns a nice 2004 Expedition. Whenever he has his trailer hooked up electrically, fuse 42 keeps blowing that supplies voltage to the driver's side trailer lights. The same trailer was checked out and used with other vehicles and worked fine not causing any trouble. It's only a 10 amp fuse so I'm wondering if a 20 amp might be better as this fuse monitors the voltage to the brake and turn signal to the drivers side. The lights work for a little while then when you go to hook the trailer back up again it doesn't work due to the blown fuse. Wondering if anyone has seen this before and has any suggestions. Any help would be greatly appreciated.

Don't put a 20amp fuse in it! You will undoubtedly find your short/ground by the telltale smoke.

 

[Calidad]

Good way to melt the fuse box too

 

[Fastcar]

Good way to melt the fuse box too

That too!

 

[Stotzbotz]

Just went by there today. The original plug connector was removed at some point and there is just the 4 wire connector hard wired in place. I unwrapped the tape and everything looks ok. I replaced fuse 42 and everything worked for a little while until the fuse blew again once the vehicle was driven around their property for a few minutes. Such a strange problem. No I won't be installing a higher amp fuse btw.

 

[whtbronco]

I'd start by tracing the wire from the trailer connector to fuse 42 in the CJB. Sounds like the problem is that wire and my guess is where the wires are under the truck.