Hi, just bought a nice 2005 superduty crew with a powerstroke diesiel. I bought to tow a decent size boat. I had big plans this weekend to tow to a nearby lake but couldn't get the trailer lights to work.

My F250 has the "TowCommand" factory installed integrated brake controller. I have two options on truckside to make wiring harness conection, a 7RV and a 4 flat. My Prestige boat trailer (2-axle) has a 5 flat so I used a standard 7RV round to 5 flat converter bought at Autozone. Note-this exact same adapter worked with my Silverado and trailer 6 months ago when I pulled from the marina with brakes, left right turn signals and running lights all working.

When I connect the 7 pin connector to my F250 and 5 flat to the trailer the F250 display gives message "trailer disconnected". Not knowing if problem was truck side or trailer side I tested out on a few friends trailers. None would light up other than running lights. On my boat trailer the only way I can get any lights is to turn on the headlights then the running lights on the trailer light up. I'm wondering if the pin layout on the F250 is different than my Silverado and just need to make new wiring harness of if the TowCommand is just not compatible with the trailer???

My current thought is there is something wrong truckside. My neighbor asked me to tow a new flatbed trailer he just bought at Lowes today. It has very simple light layout with 4 flat. Again, only the running lights work and neither brake or turning light up at all.

I did probe fuses relating to towing and all were good except backup lights (slot 20 in high amp box under the hood), this one did not show any reading. I replaced it but still did not show any voltage. Not knowing if this fuse should have power all the time I don't know if this is the problem or not.

I do have one other concern about the pin layout truckside.
The 7RV cover on the F250 shows how pins are assigned. With rectangular guide at 12 o'clock, (+) is at 1 o'clock, right hand turn/stop is at 3 o'clock, electric brakes at 5 o'clock, (-) at 7 o'clock, left hand turn/stop is at 9 o'clock and running lights at 11 o'clock position. The center position is the backup lights.
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I noticed that the RV7 adapter has 6 female openings on the perimeter, although only 5 have brass contacts. These missing locations correlate to the 1 o'clock (+) and 5 o'clock (electric brakes) on the truck side.
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If I do make a new harness, How do I go from 7 pins (truck side) to 5 trailer side? I also don’t understand why on the F250 side there is a separate pin for electric brake, doesn’t the trailer brakes activate when signal is passed to the left stop or right stop pins?


I'm hoping someone can point me in the right direction.

Thanks in advance. Toadman

 

Electric brakes have their own wire. Turn signals and stop lights are the same wire (left side-0ne wire right side- one wire). Tail lights have their own wire.

Make sure that you wire a ground thru your plug to the trailer. Most errors displayed by the Tow Command is due to faulty grounds.

Good luck

 

...and also make sure that the trailer brakes are really "electric brakes" and not "surge brakes".

 

Found that the turn single fuse under the hood was blown but bridged a bit. A test light glowed both sides but I finally broke out the multimeter and found voltage difference.

I bought trailer used through a broker who didn't know anything so got a hold of the manufacturer and found the trailer is hydraulic. The resavoir was hidden quite well and being new to trailering I'm still a novice. I guess the towcommand won't help with this type of brake. correct?

Thanks for your help.

 

The TowCommand isn't needed with surge brakes.

If that trailer has a 5 pin connector on it, then the 5th pin is probably to override the surge brakes when you back the trailer up. Backing up a surge brake trailer, particularly on a hill, is no fun unless you have a way to shut the braking system off.

I've always converted my odd connector trailers to RV 7 way plugs. If you want to do that, I'd just get a plug and use the 5 pins you'll need. Just be sure the screws inside are all tight, even if the pins are not being used.

 

No, tow command is electronic. If you can find a manufacturer for that hydraulic system, go to their web site...hopefully they will tell you how it's to be hooked up, if you don't already know how...I don't.