Montana Owners Club - Keystone Montana 5th Wheel Forum - View Single Post - Ford brake controller--"Trailer Fault" --THE FIX??

David and Jo-Anna · 07-21-2009, 02:42 PM

Thanks for all the helpful suggestions. I collected some additional data today that may answer some questions.
We spent three hours this morning towing in dry conditions. Started off getting some infrequent "trailer fault" signals when braking, but as the morning progressed, the "trailer fault" signals occurred more and more frequently, always when I was braking. I followed Art's suggestion and several times just used the slide switch on the brake controller without touching the break pedal. When I did this, I got intermittent "trailer fault" signals. More importantly, at first when I used just the slide switch, I'd get some "bucking"--as if the brakes started to grab, and then released, then grabbed again, released, in quick succession. By the end of the morning's trip, however, the "bucking" had pretty much stopped--instead, it felt like I was getting almost no braking whatsoever from the trailer brakes.
By contrast, when we were driving around this afternoon in the truck after we left the rig at the new campground, I never got a single "trailer fault" alert. I did a quick visual check of the wires leading to the receptacle in the truck, as well as what I could see of the brake wires where they come out of the trailer axles and go into the trailer wheels. All seemed OK as best I could tell. I used my multimeter to check the power to the receptacle in the truck bed. On my setup, when the brake pedal is activated, I get steady power to the two pins that otherwise provide pulsing power to the left and right turn signals when the turn signals are engaged. If that's how the brake pedal power is supposed to work, then I seem to have good power at the truck receptacle, which would lead me to believe that the problem is with the trailer brake system.
Is what I am experiencing consistent with the problem of the insulation getting rubbed off the brake wire inside the trailer wheel, as Steve mentions? Any other problem that would be consistent with the symptoms that I am experiencing? Any other testing that people would suggest I try? FYI, my plan is to try to get the rig into an RV dealer for service Thursday morning when we leave this campground--I'd like to tell him where to start looking for the problem so that he doesn't spend four hours checking things that are not the cause of the problem.

07-21-2009, 02:42 PM	#15
David and Jo-Anna Montana Master Join Date: Jul 2006 Location: Green Valley Posts: 1,618 M.O.C. #6022	Thanks for all the helpful suggestions. I collected some additional data today that may answer some questions. We spent three hours this morning towing in dry conditions. Started off getting some infrequent "trailer fault" signals when braking, but as the morning progressed, the "trailer fault" signals occurred more and more frequently, always when I was braking. I followed Art's suggestion and several times just used the slide switch on the brake controller without touching the break pedal. When I did this, I got intermittent "trailer fault" signals. More importantly, at first when I used just the slide switch, I'd get some "bucking"--as if the brakes started to grab, and then released, then grabbed again, released, in quick succession. By the end of the morning's trip, however, the "bucking" had pretty much stopped--instead, it felt like I was getting almost no braking whatsoever from the trailer brakes. By contrast, when we were driving around this afternoon in the truck after we left the rig at the new campground, I never got a single "trailer fault" alert. I did a quick visual check of the wires leading to the receptacle in the truck, as well as what I could see of the brake wires where they come out of the trailer axles and go into the trailer wheels. All seemed OK as best I could tell. I used my multimeter to check the power to the receptacle in the truck bed. On my setup, when the brake pedal is activated, I get steady power to the two pins that otherwise provide pulsing power to the left and right turn signals when the turn signals are engaged. If that's how the brake pedal power is supposed to work, then I seem to have good power at the truck receptacle, which would lead me to believe that the problem is with the trailer brake system. Is what I am experiencing consistent with the problem of the insulation getting rubbed off the brake wire inside the trailer wheel, as Steve mentions? Any other problem that would be consistent with the symptoms that I am experiencing? Any other testing that people would suggest I try? FYI, my plan is to try to get the rig into an RV dealer for service Thursday morning when we leave this campground--I'd like to tell him where to start looking for the problem so that he doesn't spend four hours checking things that are not the cause of the problem.