Blowing Fuse for car trailer?

I have an 07 Ford Diesel and I keep blowing the fuse thats supposed to charge the battery while I am driving the truck. What can I look for to see whats causing this?


Thanks Tore

Does it only do it when the trailer is plugged in? On most trailers the power wire goes to the small electric brake emergency battery first. I would check the trailer plug first to make sure it is not shorted out inside. If you have a multi-meter use the ohm or the diode setting and check from the plug terminal power wire to ground (ie the frame) to see if it is shorted out. Then trace the wire from the plug to the battery.

Tore,bring it down here and I will fix it for you.I will cut a NAIL to length and replace the fuse w/it.It will never blow that fuse ,Guarantee that. I'm a helluva electrical guy ya know.

jasonf wrote:Does it only do it when the trailer is plugged in? On most trailers the power wire goes to the small electric brake emergency battery first. I would check the trailer plug first to make sure it is not shorted out inside. If you have a multi-meter use the ohm or the diode setting and check from the plug terminal power wire to ground (ie the frame) to see if it is shorted out. Then trace the wire from the plug to the battery.

The truck I believe is supposed to charge the battery in the trl. I check the fuse in the Fuse Box under the hood and its popped. I don't know if the trl is wired wrong.
Just does it when its hooked to the trl.


Tore

bbf-falcon wrote:Tore,bring it down here and I will fix it for you.I will cut a NAIL to length and replace the fuse w/it.It will never blow that fuse ,Guarantee that. I'm a helluva electrical guy ya know.

Go back to bed!

There must be a short somewhere in the wiring. Have you checked the battery itself to see if it is alright? The RED auxiliary wire is the one you are looking for. If you don't have a multi meter you can use a test light to check it. Clip the ground wire from the test light to the positive terminal on a battery and push the test light into the Red wire connector on the trailer plug (there will have to be ground wire from the battery to the trailer chassis of course). If it lights up then it is shorted to ground.



Little jumper wires/test leads can come in handy when you are using test lights and multimeters. They can be found at your local parts store or harbor freight. They are great for jumping power from a battery to what ever you are working on.

http://www.autozone.com/autozone/accessories/Motormite-Clip-Alligator-Uninsulated-Test-Leads/_/N-25j8?itemIdentifier=297077_0_0_

One other thing... From the factory, some vehicles turn off power to the auxiliary terminal when the key is off. Keep this in mind when troubleshooting.

Tore I had the same problem a while back and figured out it was the factory plug in , something had shorted in the plug so I changed it and no blown fudes after that.....

also some of the brake away batteries have a small little box in the battery box with it is a battery charger I have seen them blow fuses many of times when they go out .Check your wiring if it all right just unplug the the charger should have a connecter to unplug if not cut the wire where you can reconnect it and see if it still blows.You should ba able to get it at a local trailer dealer if it is the charger.

Thanks for thze tips guys. I have afew things to try.

Tore

Tore,my dove tail was doing that a couple years ago and found a bare wire rubbing the side of hole as a passageway to the rear of trailer underneath. Good luck brother

Don't use an ohm meter to check a circuit unless you know that the circuit (And any close by that you might contact) is not energized. You can find voltage in the strangest places sometimes, and then you can blow the fuse in the meter (Or the meter itself)...

Glenn M. wrote:Don't use an ohm meter to check a circuit unless you know that the circuit (And any close by that you might contact) is not energized. You can find voltage in the strangest places sometimes, and then you can blow the fuse in the meter (Or the meter itself)...

Good tip, I forgot about the battery in the trailer. But, if the wire is shorted out then the battery is shorted out and dead by now or if there were a fuse at the battery it would be blown too. You could use the volt meter and check the red line first.

jasonf wrote:

Glenn M. wrote:Don't use an ohm meter to check a circuit unless you know that the circuit (And any close by that you might contact) is not energized. You can find voltage in the strangest places sometimes, and then you can blow the fuse in the meter (Or the meter itself)...

Good tip, I forgot about the battery in the trailer. But, if the wire is shorted out then the battery is shorted out and dead by now or if there were a fuse at the battery it would be blown too. You could use the volt meter and check the red line first.

ohm meter will not work on the electrc brake wire because of the maginet in the brake assy it will show ohms even with no short

69F100 wrote:
ohm meter will not work on the electrc brake wire because of the maginet in the brake assy it will show ohms even with no short

He's not working on the electric brake wire he is working on the auxiliary power wire. It supplies 12v to the battery and what ever 12v lights he may have in the trailer.