4 pin to 7 where is the 12V line?

[adamsdaddy]

I would greatly appreciate a picture of the wiring harness and part number for the "pin" (?). Does the harness tie the 12 volt line to a 40 amp fuse?

Yesterday we had the Expy at the dealership because of a brake error message and the service writer couldn't tell me where the 12 volt trailer wire was located. He said he'd look it up and get back to me today but readily admitted they had never needed to tap into a 12 volt line for a 7 pin before.

At least I can crawl under the Expy without having to use a jack and stands. I just hadn't expected to need to run a line like I did on our Honda Odyssey.

I too was surprised to learn that the only differences between HD and standard are the size of the radiator/auxiliary tyranny cooler and the tow/haul mode. Oh and that the bleeping 12 V line was run to the 7 pin.

 

[Triplet Dad]

I would be interested in the information. I have a 2007 EL without the tow package and I also went from the 4 pin to 7 pin harness for towing my travel trailer. I found the 5th wire for the brake controller but never wired up the reverse lights or the 12V power. From what I was able to find for the 12V power you have to add a relay into the fuse box and run a wire all the way to the rear of the vehicle. This seemed like a little too much effort for me for something that wasn't really that necessary.

 

[adamsdaddy]

The steps in the video to grab the tow plug from behind the dash look easy but my 2016 Expy has a vertical piece of metal which prevents me from simply reaching around to access the plug. I put it back together and I'll try it again when I have more time.

@bsevans5: how did you get to the plug behind the dash? Did you pull the radio and that whole mess or go under the steering wheel?

@Triplet Dad: having the trailer battery get charged while traveling and provide tow vehicle power to run the powered trailer jack (raising or lowering the front of the trailer) are a couple reasons why I want the 12 V. If we are running the trailer's refrigerator while towing then instead of arriving with cold food but a drained battery-everything is fully charged. We camp without hookups or a generator.

 

[adamsdaddy]

I can't get past that metal bar. My 10 yrs arm couldn't squeeze past the bar to reach the plug.

Guess I'm going to have to take out the radio and pop apart sections of the dash.

What a pain!

 

[Big Brian]

if its anything like my 2008 you can have the radio out in 10 minutes. And there is a TON of room once its removed. I am doing a Android radio conversion right now is how I know

 

[Triplet Dad]

@adamsdaddy - When I tow my TT my propane tanks keep the fridge cold. The only thing the power wire would help me is if the battery was dead when I am trying to raise/lower it or open/close the slide.

 

[Bigpappa]

I ground off the weld and removed the 4 pin mount. I made it smooth so I could install the 7 pin. I then painted over the area. Although the Hopkins 4 pin connection was smaller than that of the Ford - I jammed them together and circled them with a zip tie. I also attached the blue wire so I should have everything except power to the trailer


So what was the resolution for this? I cut back my harness looking for this mythical orange wire to no avail. Did you find it or did you run a separate wire?

 

[adamsdaddy]

It looks like I'll end up running a wire. At the moment the running light signal isn't being passed on my trailer so I have other problems. Brakes work, brake lights work, turn signals work but no running lights so I can't pull the trailer at night.

Instead of getting 9 or 12 volts I only get 2 or 4.

 

[Triplet Dad]

If all of the other lights work your running lights should also.

 

[wyldnative]

I can't get past that metal bar. My 10 yrs arm couldn't squeeze past the bar to reach the plug.

Guess I'm going to have to take out the radio and pop apart sections of the dash.

What a pain!View attachment 20345View attachment 20346View attachment 20347

Hopefully you have this figured out. I had to pull the cover from around the gauge cluster and then the side bar that holds the vent hole and a small compartment . the wire is plugged into the back of that on my '09 150.