I have a 04 F350 SD 4x4 King Ranch.
I was getting ready to tow a TT before I committed to saying I would tow I was checking my plug, usually on the 7 plug, you'd have a 12V constant and then of course trailer brakes, lighting and such. My 12V constant was showing 0.0, so I checked everything else and with lights off 0.0, but with lights on around 12V. Most of the trailers I will be towing will need the 12V constant. I have checked the fuse panel pertaining to trailer connections and all the fuses are good, I still need to keep the lid open and test the turn signals and all. Before I have Ford waste $60 figuring it out I would like to steer away from them if need be. What should I try to so I can finally get stuff back on the road and such?
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no power unless the key is on the on position.

 

I've tried KOEO (key on engine on) to get out and off and both times nothing

 

If you have the Ford tow command, it won't have power until you are moving fast enough for the door locks to lock - about 7-10 MPH. They fixed it for the 06 model year.

 

have you checked the fuses and relays? Can't get power to the rear if there isn't a complete circuit.

 

I have checked the fuses and relays, they are all good, I have checked grounding on both the 7 and the 4 connection, ground is good. I might take it to a trailer shop that I trust to see what they say. It might just be who every had this vehicle before me pluged something up wrong or sniped the 12V wire somehow.

 

Did you open the connector on the truck to look at the inside? Many say that (if the truck came from a salty environment) the connector can corrode easily.

 

Ya l've checked, I'm going to check all the fuses again, I think I might of missed one of the fuse, if work needs me to tow stuff they will need to write me a check to get fuses

 

That sounds like you were checking the parking lamp circuit, not the 12V+ lead.

You want to check between pin 4 (12V+) and pin 1 (gnd). As noted, engine should be running, and if it is diesel engine should be running for a couple of minutes.

 

Well I checked this morning before going to work, and I forgot to check fuse 115, well without pulling the fuse out, I could tell right away that it was blown, looking again at my manuel, fuse 115 is for the 12V common connection for the 7 way connection, so that answers why everything else was working except for the 12V common.

 

Congrats on the effort to figure it out!

 

I gotta say, that was a group effort!

 

The funny thing, with my old 02 Ford Explorer Sport Trac, when I installed the 7 way connector, I tied into the power outlet in the back of the bed, and the fuse was all the way in the front, now with the 350 just getting use to were some of the things are. Eventually and issue I won't need the dealer, unless I have a coupon for service.