Shorts

Speckul8r · 10-08-2005, 08:37 AM

Just bought a 2720 3 weeks ago. Leaving the dealership, I noticed that the brakes were not working. Long story short, The ouside cable running down the upright support had been pinched when the unit was lowered and smushed/cut a couple of the wires shorting them to the frame. How common is this?? If this has happened to someone else, have you discovered a log term fix? Just post someone to keep an eye on the wires as you lower the unit? I told my wife the first time I saw the arrangement that it looked like a problem area. Sometime I really hate being right.

**Bill** · 10-08-2005, 11:38 AM

Yes, I recall one other case where this happened. I have forgotten who experienced the problem (maybe Rocky Mtn Ray?), but if you use the Search tool, you should be able to find it. Just go to Advanced Search, plug in "brakes" and "wires" and maybe "axle", and scan through the results. It ought to come up pretty quickly.

Bill

RockyMtnRay · 10-08-2005, 08:23 PM

Quote:

Originally Posted by Bill

Yes, I recall one other case where this happened. I have forgotten who experienced the problem (maybe Rocky Mtn Ray?), but if you use the Search tool, you should be able to find it. Just go to Advanced Search, plug in "brakes" and "wires" and maybe "axle", and scan through the results. It ought to come up pretty quickly.

Bill

Your recollection that I had a brake wiring problem is correct; however mine didn't involve the wires along the support to the upper shell. Rather mine was the result of improperly routed (or unsecured) brake wires on the torsion suspension arms that got smooshed/cut when the suspension did multiple full deflections on a very potholed gravel/dirt road.

I've had zero problems with the wiring along the support arms to either of the upper shells (I'm assuming that Speckul8r is discussing the shell support support arms since he mentions having the problem while "lowering" the unit a couple of times...and one doesn't normally "lower" the suspension components)

Speckul8r · 10-09-2005, 08:53 AM

Correct on the shell support arm. I'm talking about the wiring that runs vertically on that arm.

**Bill** · 10-09-2005, 01:59 PM

I don't think the brake wires run up the support arm. There is no reason for them to - they are routed in and along the non-moving parts of the frame and axle, because that's where they end up.

The wires that run up the support arm (and are therefore subject to flexing every time the camper is raised and lowered) bring power to the interior lights that are mounted in the front and rear shells, and to the running lights, taillights and brake lights that are mounted on the outside of the upper and lower shells. Power to the roof mounted airconditioner is part of this bundle, of course. The TV antenna cable is also part of this bundle, since the TV antenna is on the roof.

Wires that don't bring power to something in the upper and lower shells are not routed through the upper and lower shells - and therefore not part of the bundle that goes up the shell support arms.

So I have to conclude that smooshed/cut wires in the support arm bundle are not related to a brake problem.

Bill

RockyMtnRay · 10-09-2005, 08:27 PM

Quote:

Originally Posted by Bill

So I have to conclude that smooshed/cut wires in the support arm bundle are not related to a brake problem.

Bill

Heartily second that conclusion. Brake wiring does not go up the shell support arms. Brake wiring can, however (as discussed above), be cut/broken by suspension movements. Check under the trailer, especially in the vicinity of the frame/suspension arms.

Speckul8r · 10-10-2005, 10:46 AM

But the red wire for the left brake light does go up that arm and when it shorts to the frame the Prodigy braking system no longer "sees" that the brakes are being applied. The brakes from the TM still work off the manual handle but not the pedal.
The Prodigy control box displays numbers that are related to the degree of braking being applied. The bigger the number the harder the braking. So when there is nothing displayed, nothing is happening back there. I have an '05 Sierra which has a specific fuse for the left and right individual trailer brake lights. Replacing that fuse and splicing that red wire cured the problem.
My main question was, if these wires getting caught in the supports closing mode was a common occurance. And if this has happened to others, has someone come up with a cure? Or was I just the "lucky" one.

**Bill** · 10-10-2005, 03:18 PM

Aha! You need to remember that the "brake light" circuit is completely different from the "brake" circuit.

The first runs the brake lights which, as I noted above, are mounted on the rear shell, and whose wiring is therefore part of the bundle that runs up the lift arm to the shell.

The second is power to the brakes themselves. This is a completely separate circuit, and the wires that power the brakes do NOT run in the bundle on the lift arms.

You can do anything you want to the brake lights, and it will have no effect on the brakes. And vice versa.

Bill

10-10-2005, 05:46 PM

A related note is that I have discovered that the "bullet" connectors that link the upper shell loom to the chassis loom at the bottom of the arm are a weak point. Specifically, they are subject to corrosion and create all sorts of fun when your various taillights are malfunctioning. I got fed up with the dumb things and cut 'em off and soldered the two looms directly together, covering the new joints with shrink wrap. I figured as how no one will likely ever need to remove the upper shell and therefore the looms really don't need to be disconnectable from each other.

The taillights themselves still can get some corrosion in the sockets, etc., but at least I don't have the connectors to foul things up now.

My $.02...

Steve

10-10-2005, 07:44 PM

Bill wrote:
"...You can do anything you want to the brake lights, and it will have no effect on the brakes..."

I have to humbly disagree, and I think Speckul8r's experience demonstrates this. His Prodigy controller probably uses the TV's brake light hot wire directly (rather than the brake light switch wiring) as the signal that the brake pedal has been pushed. Mine is wired this way also since in my TV the brake pedal switch is NC but the Prodigy requires a NO signal. So when his TM brake light hot lead shorts to ground at the support arm the TV's brake lights also fail and the Prodigy thinks the brake pedal is not depressed. So it doesn't automatically provide a braking voltage to the TM and the TM does not brake when the TV does.

So while the brake light circuit and the braking circuit can be considered separate circuits for most intents and purposes, they are actually linked operationally by the Prodigy controller, and one circuit going wrong can affect the other.

Paul