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Doc Mark · 10-09-2009, 08:19 PM

I have had this system for 3 years and it has worked flawlessly, until now. Yesterday when I hooked up, the compressor in the tow vehicle did not come on when I removed the breakaway pin (as it is supposed to). When I got in the coach, there were no lights on the unit & it was beeping intermittently. Went back to the toad & I fiddled with the wiring between coach & toad. No joy. So I pulled the quick disconnect apart at the electric solenoid in the toad and drove off.

I know I have no functioning brake system as is, but when I stopped for the day, the brake pedal on the toad was depressed & the RF tire was VERY hot.

How do I disconnect the vacuum pump so that I KNOW the brake isn't being applied in the toad. And how do I stop that incessant beeping inside the RV (coming from the control module)? I have seriously considered a shotgun to the part inside the coach!

I talked to a rep at US Gear & he walked me through some troubleshooting. Bottom line is he thinks there is water in the electrics between the RV & toad (in the wiring coil). His suggestion is to clean carefully all connections with something like CRC's Electric Parts Cleaner & then apply something to increase conductivity (I forgot what he told me - it was a LONG day).

In case this cleaning doesn't work I want a fall-back plan to make sure I don't have to drive another day with the beeping.

wa8yxm · 10-10-2009, 10:29 AM

While I can not help you with the beeping.. I can tell you what failure I had with the break-a-way plug

When I pulled it,, nothing..

Replaced the break-a-way switch (They are 1: Generic, 2, about 10 bucks) and when next I pulled the plug.. SUCCESS

Your problem sounds different however.. but I can tell you how to test it

The switch is very simple.. In fact I made my own for another job (Complely different application)

Imagine if you will a cloths pin, the spring loaded kind, with wires, you shove a hunk of plastic in it's jaws and there is no current path, but when you pull the plastic out the pin snaps shut, the wires contact each other and current flows.. That is the BASIC design of the break-a-way switch (IT is a long way from how it's built, but that's how it works)

Short the two wires that come out of the switch.. Or short the "hot" wire to ground, either action should activate teh brakes if the switch is bad

In my case.. The switch WAS bad.. But as I said, I think yours is different. (I did not have beeping)

I do, now, from time to time, get a quick beep and no light

I suspect the GROUND WIRE on the light harness.. Just re-did it in fact and guess what.. NO BEEPS last trip

Doc Mark · 10-10-2009, 04:05 PM

Thanks WA8XYM at least that gives me a starting place.

Mark

wa8yxm · 10-11-2009, 01:28 PM

The thing that worries me is the beeping.. Now a bad ground CAN cause beeping (On the control unit, the towed or towing vehicle or .> Well I'd have to go over the entire system to tell you all the places)

And a bad ground on teh switch (or just a bad switch ) will cause the break away to fail.

And it might be the wireing harness ground on the towed is the same ground point as the break-a-way (SUSPECT #1)

But... A bad control module could do it too, Towed end in this case.

Doc Mark · 10-11-2009, 07:38 PM

Today I had a chance to examine the electrical umbilical more closely. To my surprise it rattled when I removed it from the coach socket, and I found the the center pin was gone. So, I disassembled the large black six wire male plug. When I opened the plug I found a brass piece hexagonal & about 3/4 of an inch long just rattling around inside the plug. It appears that it connected to the now-missing center pin, but has no electrical connection. I have NO idea what its purpose is.

I surmised that maybe the brass piece was long enough to intermittently short across several terminals in the plug as it rolled around, causing the electric fault & thereby causing the beeping which is a loss-of-continuity warning.

I closed the plug up & reinstalled it on the coach & toad, and all "seems" to work. At least while we were stationary. Tomorrow I'm headed for a camping world to get a new umbilical made up.

Stay tuned!

Doc Mark · 10-12-2009, 04:02 PM

Everything worked as advertised all day today. So, I canceled the new umbilical work at Camping World.

The only thing I can figure out is that the brass piece, as it was rolling & bouncing around in the plug, would short across 2 wires.

Go figure.

Thanks for everybody's help. You guys are great!

Mark

wa8yxm · 10-13-2009, 09:41 AM

That can happen.

One of the things I plan to do,, Later, Is convert from the flat-4 + round 2, to a round 7 system (the round-2 is the US-Gear cord)

I will wire it up more or less standard..

I will upgrade the ground wires when I do this too, likely to 10 ga (I have 10 ga ultra-flex wire in stock) at least from the sockets to the frames of the two vehicles.

THen I can use a single coiled umbicial to do both lights and brakes.. I like those way better than what I'm using now... Or I can use a couple of other schemes to keep the wires from getting sliced and diced by the hitch when (if) I bottom out.

Though I hope,,, I addressed that issue, When I visited Pender and had the PROPER hitch adapter installed instead of the one my dealer sold me.

hardy1000 · 10-13-2009, 12:50 PM

Mark, I had the same problem. Try starting the toad and then try it. Thats what I did and it reset. Other than that the brake has been flawess.

Good luck

danes-on-tour · 10-13-2009, 01:30 PM

We have had a case where the compressor in the tow vehicle did not come on when we removed the breakaway pin. This proved to be a a poor connection where the breakaway pin assembly connects to the chassis.

Once we took the assembly apart - cleaned the connection - everything worked again.

We hope that your problem may be as simple as ours

Otherwise - great system the US Gear Unified Tow Brake. Simple and so quick to connect.

Doc Mark · 10-13-2009, 04:43 PM

Thanks to you all for the suggestions. It seems to be functioning just fine after I removed the brass sleeve.

Mark

wa8yxm · 10-14-2009, 10:31 AM

The center pin is not always used,, I think it's designation is "AUX" and it's sometimes used for back up lights

Considering it's size,, I wonder why they don't use it for the heaviest load on the plug (Ground) but.. they did not.

But if you look at the plug diagram.. It's pin 7 on a six pin hookup for most folks

The six, not in order, are

Right turn/brake
Left turn/brake
Brakes (The control, not the lights)
Running lights
Battery charge
and Ground

The center pin is normally N/C but as I said, can be used for back up lights. Save you don't back up towing 4-down.