Breakaway Switch

I want to pass along a recent experience to keep others from this same mistake.

I bought a M219 Heartland Edge trailer two years ago and have had good experience with it. Upon purchasing the Edge I moved it to the first trailer site where we intended to keep the trailer for a few years; not knowing on setting up I pulled the pin out of the Breakaway Switch so the cable would not be in the way. Big mistake but I was a newbie.

This weekend I was getting ready to move the trailer to a new site and did the normal inspections finding the Breakaway Switch had melted either as a result of pulling the pin two years ago or a short in the Breakaway Switch wiring.

Fortunately on inspecting the balance of the wiring all was well. It looks like the wiring in the Breakaway Switch melted and in doing so disconnected the Breakaway Switch from the battery. There is no fuse in this circuit so I was concerned that having the brakes energized for what ever time it took the switch to melt may have damaged the electric brakes.

Well it all went well; I replaced the Breakaway Switch and completed the wiring. Jacked up each wheel and spun each wheel pulling the pin on the Breakaway Switch and thus engaging the brakes which are still working fine.

I'm not sure whether there was a short or the cause was pulling the pin on the Breakaway Switch? I don't remember seeing anything on this site cautioning the pulling of the pin on the Breakaway Switch but I thought I would pass this along as a warning.

Re: ATF: Edge - Breakaway Switch

I remember reading about that near the beginning of an SOB owners manuals. I must have been bored at work because we all know how often people read instructions. I'm glad it didn't cause much harm for you.

Re: ATF: Edge - Breakaway Switch

Hi GWB,

Thanks for sharing. As you know now, the breakaway switch is intended to activate in an emergency if the trailer were to fall off the hitch and start rolling down the road by itself. The cable stays attached to the tow vehicle and as the trailer separates, it comes out of the switch. When the switch activates, the brakes are activated. Power stays on the circuit until the battery runs out of power.

The power from the battery probably goes through an auto-reset 12V circuit breaker located near the battery. If the switch had a short, it would trip the breaker, and trip it again and again every time the breaker reset.

If your switch overheated and melted, it might mean that the switch is not rated for the amperage on that circuit. Or perhaps the breaker was replaced by one with a higher rating than the wiring and switch amp rating.

Re: ATF: Edge - Breakaway Switch

Breakaway switches are fairly simple and made with simple components.

Yours did exactly what I would expect ti to do, self destruct. Running full voltage and current draw through the switch for any length of time will over heat and melt some of the components.

I don't carry a lot of spare parts or tools (but I am adding "something" to my "kit" in the future).
But, I do carry a spare breakaway, they are typically less then $10 and will keep you going.

Electric brakes are, in fact, operated with a dead short. They are simply electromagnets (very long wire wrapped around an iron core).
Depending on the size of the wire and strength of the battery the switch and wires will get very warm when the pin is pulled for more than a few seconds. There may be a fuse/circuit breaker on the charging circuit if the system uses a dedicated battery but opening the circuit to the magnets when energized would be disastrous.
GWB, I would recommend taking the drums off and checking the rust factor before towing again if the unit has been sitting outside for an extended period. Steel wool may be adequate to clean them up but you'll want to be sure they don't need more serious attention to work properly.

Thanks All for the many replies. I have checked and there is no breaker or fuse wired into the Breakaway Switch so the switch itself appears to be the fuse; it simply overheats and melts before any more damage is done. I replaced the breakaway switch and found no other damage; have checked the brakes is all is fine. Just moved the trailer 100 miles to another site and took my time testing the brakes before hitting the open road. So it appears the breakaway switch design may have been intended to do exactly what it did, it melted the small wires in the switch breaking in time the circuit and keeping more damage from occurring. It is either a clever design or one of good luck in either case I now own an extra breakaway switch which I hope never to need.

My toddler pulled mine some time this weekend. I've always been paranoid of one of the kids (or somebody else's) doing this. It got really hot fast and melted the plug when I tried to insert it. Outside temp over 30C and climbing. Since the TT is parked I just cut it out and removed it. Hopefully the brakes will be fine as they weren't that hot yet.

Off the parts store thanks to my little buddy. Wonder what else I'll find while I'm there?


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priorguy said:

Off the parts store thanks to my little buddy.

Click to expand...

Buy two. They are cheap and it is one of the spare parts I carry.

We returned home last week earlier than planned (3 weeks into a 2 month trip) because we finally sold the house after nine months! Closing on July 25th heading out full time on Aug 7th. For the first time pulling into the storage yard from the street I cranked it too hard and pulled the pin. The wire got fouled in something in the bed of the truck Fortunately I was going very slow....but it was still a jolt.

I knew instantly what had happened. Tried to put the pin back in but could not. Sent Linda out into the street as we were blocking both lanes in our direction. Turned off the battery switch...but then found out as Dan pointed out it is hot wired to the bus. Finally dropped the tail gate to climb in and get a better shot at putting the pin back in and was successful.

Don't think it was on long enough to do any damage but I think I am going to get a spare AND move the location of the switch. on my rig it is very high and up under the shroud they now put on pins.....so it was very hard to get to.

Don't think I would want it to grab going down the highway while I was pulling. Maybe I'll put the new one on and use the old one for a spare.