Wires pulled out of breakaway switch

[DRanger]

I'm having an issue on my brand new '20 2720.

The wires going into my breakaway switch housing were pulled out when I last opened my swing-away tongue. (I think they got caught up on my WDH attachments.)

I decided that since they were exposed it would be easy to test emergency braking operation by touching the now exposed ends together. When I do this I do not observe anything happening at the brakes. I've measured my battery voltage at the terminals and it is showing a healthy 12.5v so it is not due to a depleted battery.

I have tested braking function while hooked to my vehicle since this happened and I have not observed any issues there. (Except that it has always felt a little soft to me -- and I am glad to read that this appears to be at least a somewhat common issue.)

There's some good info in this thread that can help me maybe with some additional clarification:

My read of the wiring diagram included with the breakaway switch is that I shouldn't see any voltage between these two wires as the switch simply just connects positive batt to brake line hot. I think I'd only see a voltage if I measured between one of these (whichever is coming from the battery) and the brake ground line. Does that sound right?

Volt meters with loop function were mentioned to help diagnose. Any recommendations on a brand or model?

A complication I observed for diagnosing this is that I found that the wires coming from the breakaway switch run along the frame but then turn 90 degrees up into the trailer somewhere in the vicinity of behind the refrigerator. Then there are other wires coming back out of that area to the brakes. I'm hoping this is actually under the sink but not sure yet.

A complete brake assembly for TMs was mentioned as well. Any names/makes/models on that assembly?

The nearest TM dealer is a 3hr drive. If I end up going to the shop with it I am not inclined to drive it that far. I'm curious if anyone reading this has had experience taking their TM into a non-TM shop. Any issues/problems encountered doing this, least of all because of the uniqueness of TMs?

[Bill]

If you decide that a service place is the way to go, you don't need a TM dealer. The breakaway switch is mounted and wired electrically the same on every trailer. Any RV place can handle it.

If the wires pulled out of the switch and the bare ends were exposed, my first thought is that the hot wire hit some metal, and blew a fuse. With the tow vehicle disconnected, the only fuse involved is the TM's 30-amp main battery fuse. If your interior lights work with the tow vehicle disconnected, they are being powered by the TM battery, so that fuse is OK.

If you have a voltmeter, check the voltage (to ground) on each of the two exposed wire ends, one at a time. One of them should show 12 volts. If one does, power is reaching the switch, so the other one, which is connected to the brakes, is the one at fault. You will need to trace that wire. If neither shows 12-volts, you will have to trace both of them.

Let us know what you find, and we will continue if we need to.

Bill

[DRanger]

I had just found the 30A fuse at the battery this morning. It is intact.

I've checked the voltage at each wire to a bolt on the frame. One reads 1.3v the other 0v.

I bought a tone tracer yesterday and tried to use it this morning. As far as I can tell the tool is garbage. I can't quite rule out operator error and so I am still messing around with it. But if there are better tools/methods for wire tracing that anyone can recommend I'd gladly try them.

I'm probably being overprotective in balking over taking it to a random shop. But I can't shake the notion that they'll do something wrong in any set up/take down procedure and I'll get back my TM in worse shape than it went in. It's my brand new baby and if anyone is going to break it then its going to be me! I'll just have to get over this at some point, but for now I did contact TM to see if there is a local shop they can recommend. Still waiting to hear back.

[Bill]

DRanger -

The breakaway switch itself was manufactured with two relatively short wires coming out of it. As the TM was being built, each of these wires was joined/crimped to a long wire that goes back to the destination in the TM. My guess is that one of these crimps pulled apart, and your break is at this failed crimp. No guarantee, but that seems logical to me.

If that turns out not to be the case, unplug the TM from shore power, and unplug it from the tow vehicle. In this condition, the breakaway switch is still supposed to work, and I think you are saying it does not. So let's look at the wiring diagram. You can find the TM wiring diagram in the Owner's Manual in your binder. I snipped out the part that is relevant, and copied it below.

Since you have unplugged the TM from the tow vehicle, none of the 7 connections on the plug at left center go anywhere, so you can disregard all of them. And since you have unplugged the TM from shore power, the converter doesn't do anything, and you can ignore it. What is left is electrically very simple.

Power comes from the TM battery at the lower right, and goes up to the converter box through the 30-amp fuse (which you say is good). At the converter box, power is strapped across/left to the wire labelled "12 gauge black". This wire carries power to the BREAKAWAY switch. Because there is a direct line from the battery to the end of this wire at the breakaway switch, the end of this wire should have battery voltage (12 volts) on it. Since you say it does not, this wire - the one indicated by the arrow - must have been disconnected or broken somewhere between the converter and the BREAKAWAY switch.

I do not know how this wire is physically routed, so if the break is not at the crimp, you must physically trace it to find the break. All the test equipment in the world isn't going to help with this.

The easy way to handle the issue is simply to run a new wire from the breakaway switch (you probably have to buy a new one) to the destination indicated in the wiring diagram. It does not have to take the same physical path as the old one - it just has to start and end at the same places.

Hope this helps. Let us know.

Bill

[Bill]

Originally Posted by DRanger

My read of the wiring diagram included with the breakaway switch is that I shouldn't see any voltage between these two wires as the switch simply just connects positive batt to brake line hot. I think I'd only see a voltage if I measured between one of these (whichever is coming from the battery) and the brake ground line. Does that sound right?

Yes

Volt meters with loop function were mentioned to help diagnose. Any recommendations on a brand or model?

That was a mis-statement. The clamp-on (loop??) meter being discussed measures DC current (amps), not voltage (volts). There is an article in the TM Technical Library that discusses them and suggests one, but I don't think it would help you with this issue.

A complete brake assembly for TMs was mentioned as well. Any names/makes/models on that assembly?

There is no reason to consider a new brake assembly. The problem does not reside there.

Bill

[rickst29]

Originally Posted by DRanger

I had just found the 30A fuse at the battery this morning. It is intact.

I've checked the voltage at each wire to a bolt on the frame. One reads 1.3v the other 0v....

As Bill says, there is probably a short circuit on the path to or from your test points. (Or there is a broken/unconnected wire or wire nut.) I suggest tracing your "12V" voltage from the beginning, to see where things fall apart.

In my older model, behind the refrigerator, there is a wire nut with 3 wires:

1. A wire to the 12v "power distribution" load center (NOT the battery);
2. the "trailer battery charge" wire from the Bargman Cable (which ends behind the refrigerator); and
3. The wire leading INTO the breakaway switch.

If new ones are wired like my 2006 model, there actually IS a fuse on the 12v fuse board (at the end of the wire from this wire nut). If you had a temporary short circuit while moving WDH bars and/or swing hitch with an accident, you could have blown a fuse in the fuse box. So first check for a blown fuse. Then, with no Tow Vehicle connected on the Bargman cable, if you unwrap that wire nut and test for voltage - do you have "+12v" at the wire nut? If so: re-assemble that wire nut and continue.

With "+12v" present at the behind-the-fridge wire nut, move forwards along the 'street side', to find two small wire nuts where breakaway switch "input +12v" and "output to brakes" wires are connected to the breakaway switch leads. Undo one of them. Within one wire nut, ONE wire (which came behind the fridge) should be at "+12v". (If you chose the wrong wire nut, put it back together and try the other one.)

If both wire nuts have zero voltage on all 4 wires, then you have found the problem: The wire from the behind the "behind-the-fridge" wire nut has failed, with either a break or a short circuit. (The breakaway is probably blameless, and the "downstream" wire wire which is split to power the two brakes is also probably blameless.) But if you found "+12v" on one wire, then continue:
- - - -
Put the "+12v input" wire into a new and larger wire nut, along with its partner the "breakaway switch input 12v" wire and with a short testing pigtail. (Be sure that the pigtail end hangs in free air, not touching the TM frame.) With the Breakaway "pull" connector un-pulled, verify that +12v is still present on the pigtail. If +12v was lost in either case, then the breakaway switch contains a short circuit to Frame Ground. (Replace the switch.) If +12v is present in both cases, then continue:
- - - -
Re-assemble the original wire nut for the "+12v input" and one input wire to the breakaway switch, removing the pigtail. Now check the "free" wire from the other side of the breakaway switch: With the breakaway "pull" connector pulled out, it should have "+12v" as output. With the breakaway pull connector shoved back in, it should have zero volts. If either situation is not true, the switch is failed (replace the switch). Else continue:
- - - -
We have now verified EVERTHING to be GOOD, all the way past the breakaway switch and into the output wire for power to the brakes. The problem must consist of a failed connector or short circuit along that set of wires. From the breakaway "output" wire nut, one wire goes to control the brakes. If it is split to provide power to each wheel (I didn't check), the failure might be:

1. along the initial wire (broken or shorted out);
2. at a failed wire nut; or
3. along one of the "downstream" legs - wires to the individual wheels.

Now inspect and repair those "final" connections, downstream of the breakaway switch which is known to be good, to find the problem.

[DRanger]

Love the help and thanks for that diagram. I had been staring at the diagram that came with the switch itself and not at any TM diagrams. Should have thought of that.

I do have a new switch and it did come with long wires for the application. I want to know exactly what is broken before I just hook in the new wires, though.

I did hear back from TM and it was suggested that this might be covered under warranty. But it was just a maybe at this point and no recommendation of a local shop yet. IMO it was my own fault that the wires pulled and so I find this very generous of them. On the other hand, I am also starting to wonder if I ever had correct breakaway operation. If and when I find the root cause I should know more, so I'll do my best to follow these suggestions. Thanks again.

-----

Went out on my lunch break and traced the wires to behind the fridge. No wire nuts but clamps instead. Voltage coming from ... 12v distribution panel? on these lines is not present. I am getting 12v on the fridge but that appears to come from a different line source. I am suspecting a fuse but I don't know where it is ... yet.

[DRanger]

Well now things got a lot more interesting.

My fuse box did have a blown fuse. The blown fuse was one labeled 'radio' and it was actually blown before the breakaway switch event. I just didn't pay it any attention because it didn't bother me not to have the radio.

Turns out I should have paid it some attention after all. Here is where things stand:

I thought maybe the power to the radio and the brake lines were one and the same and so I thought to replace the radio fuse. As soon as the fuse made contact at both terminals I got a bright spark.

There was also a lit-up led next to the fuse. I was assuming all along that the LED meant that the fuse was blown, but now I am wondering whether it means there is a fault in the circuit. I measured the voltage across the two terminals and it was reading 10v.

Anyways, after scratching my head a while i pulled the radio and disconnected it. The red LED light on the distribution board immediately went dark and voltage across the terminals went to 0. I was also able to replace the fuse while the radio was disconnected without any issue. I am now measuring 12v at one of the two breakaway lines.

In short ... there's a short in the radio!

However, even now that I am reading 12v on one of the two breakaway wires, I still don't hear anything happening at the brakes when I connect the two lines. So ... still need to dig in further there.

Kinda feeling like warranty service is ... warranted ... now.

[DRanger]

So, I looked and looked and looked and couldn't find anything wrong with the wires. What's more, the brakes work when hooked to the TV and at the point behind the fridge, the line from the bargman and the line from the switch become one and the same, so, logically the switch line should work too.

So this morning I lifted the wheels, turned them, and energized the switch line and the wheels immediately stopped.

Apparently there's no movement or clicking to be heard in my wheels when the brakes are energized while the wheels are not moving.

So, I think all is well. Nothing is wrong with my brakes, or, nothing will be wrong once I install a new breakaway switch.

The radio short was the problem (but I just didn't know it) and it took tearing out my breakaway switch wires to discover it!

[Bill]

Originally Posted by DRanger

Apparently there's no movement or clicking to be heard in my wheels when the brakes are energized while the wheels are not moving ... So, I think all is well. Nothing is wrong with my brakes, or, nothing will be wrong once I install a new breakaway switch.

That sounds right.

When you energize the brakes, what you are doing is energizing a magnet, which rides very close to a smooth steel surface (part of the hub/wheel assembly). When energized, the magnet closes the small gap. If the wheels are not rotating, you hear nothing because the gap is so small. But if the wheels are rotating, the next thing that happens is that the magnet drags over the surface as the wheel turns. The dragging of the magnet is audible.

Incidentally, if you apply the tow vehicle's brake pedal, you can sometimes hear "singing" at the TM brakes, even if the wheels are not turning. The pulsed voltage from the controller causes the magnet to vibrate a bit against the steel surface, and you can hear the vibration. Not always, and not from the breakaway switch, since it doesn't produce pulses. But when you can hear it, it is an easy indicator that power is getting to the brakes, even if the wheel is not turning.

Bill