1999 F-350 7.3 dually.
I have no 12v power coming out of my trailer plug to charge travel trailer battery?

Is there a fuse somewhere or where does that power come from?

 

Do you have your ignition turned on?

Steve

 

yup had the ignition on I drove for 200 miles and nothing charged up , thats when I started checking further.

 

Relay or fuse then would be the obvious selections, although you may simply have a corroded seven pin making poor contact, usually on the back or underside of the rear of the truck. The seven pin receptacle is an ongoing problem child. Check with a volt meter on the charge pin, but give the fuses and relay a once over. You did your checking after it didn't charge with the ignition on right? A relay will open and kill the charge output when the ignition is off.

Has this system been working in the past?

Steve

 

is there a good battery to charge?

 

Where and which relay?
I imagine the syestem worked im the second owner and the other owner pulled a 5th wheel trailer all the time.
Everything else works./

 

Did you have any luck finding a fuse or relay? My 2005 Super Duty has the same issue--no power on pin 4 when the key is on the "on" position and running.

 

check the relays under the hood at the power dist. box. Should be a legend there or in your owners manual for your year.

 

This is for Ken (Vinford).

This should be, in fact, quite simple.

See the attachment below for some assistance to this problem:

There is a small "doghouse" that sits beside the under-hood fuse box. Make sure both relays are in there, and Fuse 24 in the under-dash fuse box, and Fuse 18 in the under-hood box.

Pop

 

Here's that relay box:



Pop

 

Thanks for the reply guys. I was able to determine that it was fuse "107" under the dash. This is a light blue 20A square fuse in the top row second position from the left. Thanks again.

 

Underhood fuse gone thank you.