MOCTAP

[noneck]

We had the pleasure of attempting an assist our fellow MOC'ers -> KiwiRVer. They happened to be passing our area and have an issue with electric brake system...
2008 F350, 2010 Montana Mountaineer 326RLT
Our attempt to determine failure was unsuccessful tho and would ask others "if" they might have solution or input.
On arrival in our local Park-n-Ride Craig indicated the problem was not present since leaving prior location in Plymouth, Ct.
We performed the following tests;
1. Read truck stored codes as no "active faults" and found one, C2807 -Trailer Brakes Wiring Circuit Short to Ground.
Connected a debug tool of mine which uses an old Teknoshia Sentinel wired to a trailer socket via 4 wire long tail...
2. Checked for current using an amp meter for each wheel
3. Checked by jacking each wheel off pavement, spin apply braking
4. Inspected connections and wiggled wiring in axles while monitoring for short circuit.
5. Resistance of entire trailer brake circuit was typical at 2 ohms.
**Finally was at a loss that we could aggravate a failure and left them to continue on their travels.
They did say it reoccurred abouth five minutes down the road but then went away for the remainder of the trip to their current location.
...intermittent problems can make for real challenge...

If anyone has thoughts on this...please post your idea's

[Carl n Susan]

The 2008 Fords have a known problem with "Trailer Faults". There is a TSB on the issue which involves sealing the plug assembly. It tends to leak in wet conditions and that causes intermittent shorts. Because it is intermittent, it is a bugger to diagnose.

I used to have the fault message when traveling in damp Oregon but never in dry Arizona. Once Ford sealed it up the faults were much less frequent.

[Ishler]

This symptom is typical of one of the solenoid wires rubbing through the insulation and shorting to the drum of the trailer.

[scductman]

I had the same problem with a sob. Mine was the plug on the cord coming from the fw it would make connection sitting still but when you started down the road it would lose brakes. I changed the controler trying to find it. the plug looked good but it was the trouble. just something to ck.
Bobby

[KiwiRVer]

Let me firstly express our extreme appreciation for the assistance that Noneck provided. I used the MOCTAP list and it worked. Chuck was not only very helpful and took time away from work to help us, he had all the gear necessary to diagnose the problem if it had been present but unfortunately it stubbornly refused to appear while we were with him.

I did take the advice of a very good RV tech I know and removed the plastic clips that hold the wires as they go through the hubs. I replace these with self sealing tape. The clips certainly do not do the wires any good with a very tight bend and the wires are solid conductor however there was no evidence of fraying and the fault showing on the truck computer was grounding, not open circuit. Last trip we had no faults but I am not convinced this was why.

I am keeping a watching brief and will advise if we ever do find the real problem.