Trailer connection for flat towing

[SilverFox-THOR]

We own a 2024 Thor Delano Class C Motor Coach based on a Mercedes Benz Sprinter 3500 chassis. After purchasing 2024 Ford Maverick Hybrid and having it set up to flat tow, and hooking it up to the motor home, we discovered the electrical connection has a short somewhere. Has anyone else encountered this problem? We've has a certified RV electrician check this out and he cant find the source of the short. We've had to cancell a long planned trip due to this, because we cant safely flat tow w/o functioning lights on the towed vehicle.
The mechanic is attempting to contact Thor for advice, a wiring diagram, and new wiring harness for the trailer connection. This situation makes the motor home virtually useless to us for our intended use.

 

[SGilbert]

Trailer wiring is fairly simple.
Have your "certified RV electrician" start from scratch and rewire, but if it were me, I'd take it to a trailer hitch installer and have them have a go at it.

 

[EA37TS]

How do you know the short is on the Motorhome? During my installation there was a short in the wiring installed on the Jeep. Took a RoadMaster tech coming to the house to find and correct the problem.

 

[Lt Keefer]

Trailer wiring is fairly simple.
Have your "certified RV electrician" start from scratch and rewire, but if it were me, I'd take it to a trailer hitch installer and have them have a go at it.

Bingo. I'd also find a new electrician.

 

[pwoods]

I had a trailer specialist set up my Maverick including Demco Stay N Play braking system. Just completed 2500 miles of towing with no problems. SGilbert has the best idea: start over to make sure the wiring is correct.

 

[psdtime]

I don't know much about how it is set up, but I'm willing to bet that the towing harness on the RV was set up by Mercedes, not Thor. When you say it has a "short", is it blowing fuses or just does nothing? If it does nothing, check the Mercedes fuses, bring out the manual and find which is for the trailer harness. If it is blown, replace it, make sure you are not plugged into the Maverick. If it is shorted to ground, it will just blow again, if not, check it again by hooking up the Maverick. If it blows again, try to find a different trailer and see if it blows on that too. If I was a betting man, I would guess that they hooked up the seven pin connector wrong on the Maverick. I had to replace one the other day on a car trailer the instructions that came with the plug were not correct to my factory Ford and GMC trucks. I had to uses a "Power Probe" to identify the trailer wires and hook it up. For anyone that tows a trailer or toad, I would strongly suggest having a "Power Probe" (or something similar". Something like this might be helpful to check the Mercedes wiring, https://www.amazon.com/CXTM-Trailer...5852-B091GLV8H8-&hvexpln=73&gad_source=1&th=1 , but I still think it's how they wired the Maverick.