Brake help

Crawl under the rear of the truck and see how the cord is wired to the truck. Mine was spliced into the wiring with those plastic slice connector. After a few years those connections corroded and I had intermittent brakes. Rewired it all and all is well.

Vulcaneer wrote:

TheAmRheins wrote:
The brake wire that runs through the axle tubes is possibly frayed inside the axles.

The key is it is INTERMITTENT. Grounds, factory brake controller, and plug connections usually are not intermittent. Although sometimes they can be. But not usually.

Quote above a strong possibility. As well as, a wire inside the wheel hub has just started to rub through. And when the brake levers engage they move against the wire. Sometimes it shorts out. Sometime it may not. Eventually the problem will get worse, as the worn insulation area gets larger.

Best to remove the wheels (one at a time) and check the wires in the hub very closely. Especially where they run close to any movable metal levers. This can be quite costly for labor. But not for parts. The fix can be as simple as installing a piece of shrink wrap insulation. And re-routing the wire so it does not rub anything.

X2
I blamed Ford for an entire season, and I had tried everything I could think of. Then one day the RV shop tech walked up front dangling a magnet with cut wires out of the 5th wheel. He was doing a routine inspection and said - "found this. The wires were cut and grounding to the backing plate, did you ever notice a problem??" Never another sound out of that controller for the last 8 years.

PS - my brakes would lock, but what I didn't notice is it was only 3. Have someone hold the brakes and you walk around with a compass held close to each wheel. The needle should move as a result of the magnet in each wheel. If not - you have an issue.

TheAmRheins wrote:
The brake wire that runs through the axle tubes is possibly frayed inside the axles.

The key is it is INTERMITTENT. Grounds, factory brake controller, and plug connections usually are not intermittent. Although sometimes they can be. But not usually.

Quote above a strong possibility. As well as, a wire inside the wheel hub has just started to rub through. And when the brake levers engage they move against the wire. Sometimes it shorts out. Sometime it may not. Eventually the problem will get worse, as the worn insulation area gets larger.

Best to remove the wheels (one at a time) and check the wires in the hub very closely. Especially where they run close to any movable metal levers. This can be quite costly for labor. But not for parts. The fix can be as simple as installing a piece of shrink wrap insulation. And re-routing the wire so it does not rub anything.

Check the ground connection on the connector!
Verify that both ends are correctly grounded to the FRAME and both battires are correctly grounded to the FRAME.
Bad grounds cause way more issues than they are given credit for.

Try pulling some other 5ver to see if it does the same thing. Process of elimination.

I don't fault him for not wanting to go anywhere so this needs fixed.
First things first. I highly reccomend you do what is told to you by the good folks here or have your Father in Law or whom ever is working on it come here and read everthing first hand. These things are tough enough without loseing anything in translation.
Pulling the break a way cable sounds like a good way to test from junction box to brakes.
If it passes that test you need to check from junction box to controller. I would start by diassembling both sides of the plug for inspection,clean and tighten wire clamping screws.
Chances are if there is a loose conection,it will be discolored due to high amp draw of brakes. Next to junction box where plug pigtail mounts on trailer.
It's possiable but itermitint controller failure is very unlikly.
Pulling a friend's trailer or loaning his trailer(with a caution of course)could bring it down to almost certainly controller with possiability of truck wireing. Controllers are almost plug and play so borrowing before buying might be an option.

Here is couple problems that showed on a quick search. I would stop by a Ford dealer and see if they have any tech bulletins or troubleshooting in their system.
More issues
Ford controller test

TheAmRheins wrote:
The brake wire that runs through the axle tubes is possibly frayed inside the axles.

Thats the first thought I had because of the random failure mode.

Water-Bug wrote:
The next time that it happens, I would yank the trailers brake breakaway cable and see if it locks up the trailer brakes. That would at least give you a starting point. If the brakes lockup, suspect the truck's brake controller or the connectors. If the brakes don't lockup, the problem is definitely in the trailer brakes.

EDIT You may want to unplug the trailer from the truck, befor yanking the breakaway.

That certainly seems like an excellent troubleshooting method!
I'll file that in my memory bank and hope to be able to retrieve it if need be!

The next time that it happens, I would yank the trailers brake breakaway cable and see if it locks up the trailer brakes. That would at least give you a starting point. If the brakes lockup, suspect the truck's brake controller or the connectors. If the brakes don't lockup, the problem is definitely in the trailer brakes.

EDIT You may want to unplug the trailer from the truck, befor yanking the breakaway.