08 F-250: no power to trailer

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hljantz

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Jun 10, 2007
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Just returned from my local hitch shop where they transferred the 5W hitch from my old truck to my "new" one.  I also asked them to install the electrical connector in the box wall and get it powered up.  I understood this was a relatively simple thing to do since the truck is an 08 F250 and has the tow package and the built-in brake controller.  Well, here's my problem.  They did everything but actually connecting the wiring.  They were hesitant to take the final step and "plug the thing in" because there was no power to the existing trailer connection they would be "pluging into" and they figured if they messed with it, Ford would claim they had caused the problem.  I guess I appreciate their caution. 

They are under the impression that maybe the circuit back there needs to be activated by a Ford dealer.  I find nothing like that mentioned in the owner's manual.

Any ideas?
Thanks,
Herm
 
There should be a circuit breaker that has to be installed in the power distribution box under the hood.  Look for the directions on the location and how to install it in the owner's manual. Mine was wrapped up with the trailer brake pigtail in the glovebox.
 
My F-150 had the stuff & directions in a plastic bag in one of the door pockets. I also had to install the relay that Bross talks about & a fuse. Both of them went in the fuse panel.
 
There are 2 Relays you need too install in Power Distribution Panel located on Passenger side kick panel too power up your Brake Controller and your 12v power(charge-line)too your CEO . they should have been in a plastic bag in the glove-box this is part off your Tow-Package if not you can pick them up at your local Ford Dealer
 
Hi, Herm,
Have you checked under the hood where the fuse panel is? Sometimes they leave the fuse out until ready to hook up. Check all the fuses.
www.anyrvpart.com
Thanks,
Robin
 
Way back at the beginning of the month I posted a request for help because I was having problems getting power to the trailer from my new (to me) F-250.  I've been out of town for most of September, but now I'm back and I need to resolve the problem. I appreciate the responses I received from four of you and I addressed the problem in the ways that you suggested.  Still just have limited power and I feel I'm missing some obvious thing.
Here's where I'm at:  At the 7 way connection at the back of the truck I have 12 volts on #4, the battery charge circuit and I have good continuity to ground on #1, the ground circuit.  Other than that, I have nothing.  All other terminals read zero.
I have carefully checked the power distribution panel under the hood and the fuse panel on the passenger side firewall.  Everything seems to be in order with fuses/circuit breakers all installed as called for.
To the extent possible I have visually inspected the wiring under the back of the truck and it looks fine.
What am I missing here?  Is there a disconnect that I'm not aware of or is the disconnect in my old head?
Thanks again for the suggestions already given and thanks in advance for any future help you can give me.
Herm
 
I don't understand the problem you are having. The other terminals on the plug are for tail lights, turn signals brakes and brake lights. Is that what you're having trouble with? I was under the impression you weren't getting 12 volt power to the trailer.
 
The number 4 terminal is hot.  2.3.5. & 6 are not.  And yes, I have had the lights on, turn signals on, etc. when I tried to measure a voltage.  I even drove out to where the trailer is stored and hooked it up, hoping for some strange magic but nothing worked there either.
I forgot to mention that I talked to the folks at a large local Ford dealership regarding the possibility of an activation procedure of some sort, but the people in parts, the people in service, and the people in new vehicle "make ready" said they'd never head of such a thing. They said when new trucks come in they are ready to roll.
Thanks for giving my problem some thought!
Herm
 
I think the advice that Master Tech and others gave about inserting a relay and/or fuse is right. Ford's usually have a bag with the required parts in the glove box or door pocket when delivered.  Ask a different Ford dealer or call Ford Customer Service.  Failing that, take it to the dealer for warranty service.

Is the 4 pin connector dead as well? (you should have both a 4 and a 7 pin trailer plug).
 
I had similar problem with GMC, it was missing a 30 amp fuse, no biggy once I figured it out, but  wondered why they would design and sell a rig to tow with, and then not put in the needed fuses?
 
Yes, the idea of a missing fuse keeps coming back to me and tomorrow I'll check that situation again.  It appears from the fuse/circuit breaker charts however that each of the functions (stop/left turn, stop/right turn, parking, and running) are fused separately.  I feel like I'm missing a disconnect someplace although I guess it's possible that I have a sliced cable or something like that. 
Thanks for your help.
Herm
 
Stop/left turn, stop/right turn, parking, and running are fused separately but those circuits are for the lights on the truck. There is also a separate circuit for the trailer wiring harness.
 
No, there are separate circuits for the trailer.  The labels read "Trailer stop/turn (Left)", "Trailer stop/turn (Right)" etc.
Herm
 
Not sure about Ford, but in GMC products there is separate 30 amp fuse for the power to the inverter, and it is not in the same fuse panel as the turn and stop light fuses. it's in a box under the hood. Turn signals and every thing will work fine, except no power to the inverter. It's the center connector inthe plug/receptcle. Check this to see if you have power to that point, if not start looking for the fuse.
 
What you describe is sort of the opposite of my problem.  The only power I have is the 12 volts to the 4 pin which is the battery charge circuit. All the rest are dead. (We must be operating under different systems because for me the center connector is the back-up light circuit.)  I went through and carefully double checked everything today and I can't find and problem with fuses or relays and the wiring in the back is fine as far as I can check it.  I'm afraid I'll have to throw in the towel and take it to my Ford dealership.
Thanks for your ideas.
Herm
 
OK all you have is 12volt at the 7-way plug, and nothing else correct?? and the 4-way flat is dead too correct?? you have seperate fuses at the box for lt turn,rt turn, stop.. clearence.. if you have good fuses then you must trace the wires from the front to the back, sounds to me like you've got a harness cut in two somewhere along the frame. never seen a fuse problem with turns,and stop , clearence all at one time. kevin
 
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