[jeostang]

I'm guessing I blew the fuse because I was winching the car into the trailer, the winch was getting slow and stopped. So I put a battery jumper box on the battery in the trailer to finish pulling the car in (the winch pulled really fast with that box attached). This morning nothing worked that draws power from that battery, and the battery only had 5 volts, turns out the fuse in the truck was blown. I'm trying to figure out what blew the fuse.

1.) The winch was drawing too much power
2.) The battery jumper box was too much for the 25 amp fuse.

 

[markadams]

The truck battery had only 5 volts? After driving it home too? IMO you were pulling to much power for that 25 amp fuse.

 

[jeostang]

Battery in the trailer had only 5 volts.

 

[rattletrap]

Is the wire from the truck supposed to be charging the battery in the trailer while towing? If so, it sounds like the fuse was already blown because it was not charging the trailer battery or you would not have had to use jumper to start with.

 

[jeostang]

Yes that wire switched power on the round plug, I wired it to charge the batter in the trailer, then the batter goes to an inverter. My tongue jack worked before leaving, with the truck running. Nothing worked when I got back home. Everything is working now after replacing the fuse.

 

[skyhawk jr]

Happens all the time on our f350 also. Fuse blows in the truck at random. Not sure what does it

 

[rattletrap]

Everything works with a dead battery because you replaced the fuse??

 

[jeostang]

Everything works with a dead battery because you replaced the fuse??

Battery isn't charged it, but replacing the fuse now allows power to get to the jack and winch with the truck running. And the battery is charing again.

 

[rattletrap]

Yes that wire switched power on the round plug, I wired it to charge the batter in the trailer, then the batter goes to an inverter. My tongue jack worked before leaving, with the truck running. Nothing worked when I got back home. Everything is working now after replacing the fuse.

Just trying to figure out why you would need an inverter to run a 12 volt winch off a 12 volt battery?

 

[old man joe]

I would load test the trailer battery , if it is bad it will pop the fuse. The winch and tong jack will run try to run off the truck battery instead.

 

[garychios]

The winch pulls power from battery. If battery too low, it will draw more power from truck. Change trailer battery.

 

[rattletrap]

Send that winch to racerrob333 he will know what to do with her !

 

[BLS 6T7]

Do you know for sure that the wiring from the truck battery to the trailer battery is able to handle the max load that it may see. That sounds like the most likely problem. If the fuse blows you may not realize it until the trailer battery runs down which is what you experienced. Need to hook up a amp meter to see what the max draw is and is the cable gauge large enough. Was the wiring from the truck battery just supposed to handle lights etc. or purposely designed for the winch and/or jack also?

Skyhawk Jr said that he sees it randomly on his F350. Possibly the same issue.