All of us usually have a can of WD40 in the door storage. I squirt some WD40 into my 7-way trailer connector on my pulled trailer everytime I hook up. I move the 7-way plug around real good a couple of times to make sure the contacts all get exerised abit with WD40 spray.
Seems to work good for my trailer connections...
My 2010 FORD TRUCk has the built-in OEM brake controller and I sometimes get the disconnect message on my info screen. This seems to be more sensitive than my previous Prodigy after market Brake Controller.
I am a WD40-DUCK TAPE fixit guy here haha...
Roy Ken