Brake issue

[Hebert2756]

I am pulling a model 3612 with a 2014 dodge dually diesel. The information center keeps beeping and saying check trailer brake wiring or trailer disconnected. When it says this all the lights and turn signals still work. My friend brought over his model 3712 and I hooked up to it and pulled it with no error message and then he hooked up to mine and pulled it with no error problems. I have had it at an rv dealer for 2 weeks and they say there is nothing wrong with the trailer wiring. I took my truck to the dealer and they checked everything and said there is no problem. Thank you for reading and will take any suggestions.

[JRTJH]

Ford uses a Bargmann 7 pin connector, Keystone uses a "generic" Pollak connector. Sometimes (not always) the pins don't match well and there will be a "jittery" connection. When that happens, the truck computer detects the "loss of trailer signal" and tells the dash display/trailer brake controller that there is an error. The computer diagnoses the error as "trailer disconnected" or "trailer wiring error".

Clean the connectors on both the truck and the trailer, apply a liberal (huge) coating of di-electric grease to both. If that doesn't fix the problem (it probably will) then get a new "BARGMANN" 7 pin umbilical harness and replace the wire/connector on your trailer so it matches your truck.

You can buy a Bargmann 7 pin connector, cut the end off your trailer and install it, but I've found that replacing the entire umbilical causes less potential problems when the chips are down and you really need it all to work properly.