# Intermittent Trailer Brakes



## CJ999 (Aug 11, 2005)

I'm driving a 4WD 1995 F250 7.3L Turbo Diesel with a Prodigy brake controller, towing a 2005 28RSDS with about 15k miles on it.

900 miles into a 2000 mile trip, whilst cruising happily along highway 30 between Portland and Astoria, I started getting an "O.L." code on my Prodigy controller and it was clear that my brakes were not working when I was getting that code. It was intermittent. One time I would put my foot on the brakes and get a brake response from the trailer that degenerated into a overload with no brakes, and then the next time I would get the overload code from the start and then end up with brakes a second or two later.

It wasn't really a dangerous situation once I became aware of it because my truck could manage the brakeless trailer as long as I drove smartly. I made it home 1100 more miles in this condition with no close calls or anything, I just drove like I had no trailer brakes and was happy when I got them.

Back at home, I have driven my truck with a different trailer and determined that it isn't the truck.

With my truck hooked to my Outback and me in the cab stepping on the brakes, I had a partner wiggle the brake wires at the axles. We re-created the situation over and over while wiggling the wire that enters the the rear axle.

Does anyone know if this wire does anything inside that axle besides transfer electricity from one side of the trailer to the other protected by the axle?

I surmise the wire may have a crack in the housing or something that's causing a short... thinking of testing this theory by running a wire that isn't fed through the axle directly across... but any insight would be greatly appreciated.


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## MJRey (Jan 21, 2005)

On a couple of recent trips I've had issues with the brakes and getting intermittent fault messages, primarily the short and overload. It turned out to be the connector on the trailer. I cleaned the contacts and then bent them in to get a tighter contact. Since doing that the problem went away. It's a pretty easy fix and I would start there before chasing wiring all the way back to the brakes.


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## CamperAndy (Aug 26, 2004)

I suspect a rubbed wire to the magnet in at least one of the brake drums.

It will take two people but connect a volt meter set on ohms to the trailer connector (brake input and ground) and then turn each wheel by hand, you will need to jack the trailer up. While you do this, when a high spot in the drum touches the bare wire the resistance will drop.

A second option will also require two people, pull the trailer at 2 or 3 mph and apply the brake with the manual control. Just enough to get the brakes to start to operate. As you pull past an observer the brakes will disengage when the wire shorts out. You can easily pick what side this happens on but which wheel can be tricky.

The biggest issue is that it is intermittent. If you get no response from either test then you will need to pull each drum and inspect.


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## TwoElkhounds (Mar 11, 2007)

I had a similar issue on my 25RSS a few years back. Like Camper Andy said, it is likely a rubbed wire in the connection to the magnet. These wires are routed with a metal clip inside the drum that will chaff the insulation, eventually causing an intermitent short. I would pull all four drums and wrap the wires with electric tape in the area where the clip holds the magnet wire. I would steer away from the standard plastic electric tape since the drums can get hot and the plastic tape will degrade quickly. I used fabric mesh electric tape (not sure what the technical name is) when I made the repair. The bad news is the repair is a bit of a pain in the butt, the good news is that it is a cheap repair.

DAN


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## Jewellfamily (Sep 25, 2010)

I had problems with my chevy and my last TT doing the same thing (trailer brakes intermittantly kicking out). Mine was a corroded contact in the trailer receptacle on the tow vehicle. I had to sand it off a little bit and clean out the plug with contact cleaner.


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## CJ999 (Aug 11, 2005)

I figured if it was the connection plug, I would be seeing more than what I am on the Prodigy controller so I didn't spend much time inspecting it. But based upon all the comments, I think I am going to spend some time looking at it today in hopes that it might be the source. I doubt it though. I never get off easy!


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## wolverine (Mar 5, 2009)

I am having the exact same problem with my trailer and Prodigy P2, except I have all new brake assemblies. I can sometimes go 200 to 300 miles without having a problem and then the brakes kick on during a stop for a few seconds and then it reads OL then SH. During a stop at a gas station I wiggled the wires in the rear axle and then the brakes worked for 600 miles. Now they won't work at all. I am going to replace the wires in the rear axle this week.


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## CamperAndy (Aug 26, 2004)

wolverine said:


> I wiggled the wires in the rear axle and then the brakes worked for 600 miles. Now they won't work at all.


Yea that is another common location for a rub to occur.


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## wolverine (Mar 5, 2009)

Here is a picture of the wire that I pulled out of the rear axle today. This trailer does not really have that many miles on it for a 2004, because the previous owners never used it much and they stayed close to home. I think the wire was stripped bare in two places during installation. I never knew I had a problem with my brakes until I bought a Prodigy P2. My old brake controller would not show any faults. These are excellent brake controllers.


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## CJ999 (Aug 11, 2005)

WAHOO! My brakes are repaired! And it wasn't that difficult!

Turned out to be the exact same problem as the gentleman from Southwest Michigan, the insulation on the wire running through the rear axle was torn and the wire was consequently exposed.

I snipped the wire at one side and pulled it out. At first I thought I was chasing up the wrong tree but then I found the damaged spot about half way across. I snipped it out, spliced it with butt splices, and just ran the wire on the outside of the axle. I fastened it to the upper rear of the axle. Maybe a little *******, but at least it works. Actually, after I finished the first wire, I decided I better pull and inspect the other so I did both. The front axle had no problems, as I suspected, but better safe than sorry.

I took the setup out for a test drive and I gotta tell you, after driving 1100 miles with NO BRAKES, I was conditioned to put my foot on the truck brake pedal at a certain point before I needed to stop. This resulted in me stopping about 30 yards short of where my brain thought I would stop! It was fun! I don't know if it's just the mental conditioning of having worked my way home on the long trip without brakes, or if the damaged wire had actually been affecting my braking distance for a long time, but I don't think the truck/trailer combo has ever stopped as efficiently as it is now.

Thanks guys!


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