Testing Breakaway Switch

[cytaylor]

Hi, y'all. New (to us) trailer and I'm trying to make sure all the stuff that must work actually does, and the breakaway switch has me stumped. Our 98 Classic has the Tekonsha 2010 switch. Is this wired directly to the trailer batts? From other posts, this appears to be the case.

I've cleaned it. When we pull the key to test, I do not hear any clicks, buzzes, or snap crackle pop from the brakes. I should hear something, right?

What can I do to determine if I should replace this switch?

Thanks!

[Kevin245]

The simple way would be to hook up, then pull the pin and try to move your AS.

Keep the testing brief, and do not plug your AS umbillical into your tow vehicle while you have the break away switch activated. It could damage your brake controller.

Regards,

Kevin

[HowieE]

Another way would be to have someone stand next to the wheel and hold a compass close to the wheel just below the center of the wheel. As you pull the pin the compass needle will move if the brakes are in fact getting power. The compass also is a fast way the check brakes while traveling and you think you have lost a brake do to a broken wire. The failed one will not move the needle.

Yes the Emergency Switch is wired directly to the battery.

An important consideration that all to many don't understand is the wire from the switch to the TV should be short enough that if the hitch or ball brakes the pin is pulled before the chains reach there limit. It is a good idea to route the wire through a clip placed in the ball trigger. This insures the wire can't snag on other parts and defines the shortest routing of the wire. Many have the wire draped below the hitch with so much slack it would never pull the pin on a hitch failure.

[Bluto]

Yet another way is to jack the trailer wheels off the ground and spin the tire and pull the pin. Tire should stop right away.

[Lumatic]

Before you pull the pin disconnect the umbilical. If you don't you may fry your brake controller in your TV.

[cytaylor]

Tell you the truth, this forum has lowered my blood pressure from the "holy smoke" range back down to almost normal. I've been able to run down every issue (real or imagined) I've come across in the 2 weeks we've owned this unit (our first). Even though I've read almost every word in the manual and bought all the books anybody recommended, it's this forum that has ended up saving my bacon every time. Thanks.

[B25guy]

When I shredded a front curbside tire a little bit ago, a piece of shrapnel apparently yanked the wires out on the rear curbside brake.

Finally got around to fixing that last night and wanted to test the fix before hooking up for my next trip. While it was still jacked up, I pulled the breakaway...nothing, both curbside wheels rolled. Got the meter out and found I had 12v on one side of the switch and nothing on the other side. Stuck a screwdriver in and got a little spark and lo...brakes locked.

Looks like a combination of corrosion on the contacts and a weak spring to force the contacts together...the contacts were just far enough apart that the switch was rendered useless.

Got a new switch and going to test this much more often (versus once since I bought it new).

Marc

[Wingeezer]

Originally Posted by HowieE

Another way would be to have someone stand next to the wheel and hold a compass close to the wheel just below the center of the wheel. As you pull the pin the compass needle will move if the brakes are in fact getting power. The compass also is a fast way the check brakes while traveling and you think you have lost a brake do to a broken wire. The failed one will not move the needle.

Yes the Emergency Switch is wired directly to the battery.

An important consideration that all to many don't understand is the wire from the switch to the TV should be short enough that if the hitch or ball brakes the pin is pulled before the chains reach there limit. It is a good idea to route the wire through a clip placed in the ball trigger. This insures the wire can't snag on other parts and defines the shortest routing of the wire. Many have the wire draped below the hitch with so much slack it would never pull the pin on a hitch failure.

A couple of excellent tips, thanks!

Guess I couldn't use my gps instead of my compass? (jus' kiddin")

As for the length of the cable on the breakaway switch, I ever considered that before. I guess in shortening it though you'd need to be sure it couldn't pull the pin on a tight turn if you get it too short.

Brian.

[HowieE]

I feed the umbilical and the break away cable through a clip on the tongue. This insures against snagging and defines the shortest distance for the cable.

[Chuck]

Originally Posted by HowieE

An important consideration that all to many don't understand is the wire from the switch to the TV should be short enough that if the hitch or ball brakes the pin is pulled before the chains reach there limit.

Completely disagree, there. IMO, the trailer brakes shouldn't be activated unless or until the trailer has completely disconnected from the tow vehicle. The chains are there so that they CAN reach their limit, and continue to keep the trailer connected. In such a situation, you are still able to bring the truck and trailer to a controlled stop; Only if they fail, do you want the trailer's brakes activated. Having the trailer slam on its brakes, full-force, while its still connected to your truck, could really ruin your day.
as such, the break-away cable should be longer than anything else, and it should be connected to something other than the hitch or receiver. (if the cable is connected to any part of the hitch system, and it falls out, the pin won't pull, and the trailer will go on its merry way). I replaced one license plate bolt on my truck w/ an eye-bolt, to which I attach the break-away cable.

[BogieGolf]

Originally Posted by HowieE

I feed the umbilical and the break away cable through a clip on the tongue. This insures against snagging and defines the shortest distance for the cable.

Hi HowieE,

Great idea!

What do you clip the other end of the break away cable to? (Not sure if this is correct, but I clip mine to the factory loop on my GM hitch designed for safety chains )

Cheers,
Chris

[HowieE]

Originally Posted by Chuck

Completely disagree, there. IMO, the trailer brakes shouldn't be activated unless or until the trailer has completely disconnected from the tow vehicle. The chains are there so that they CAN reach their limit, and continue to keep the trailer connected. In such a situation, you are still able to bring the truck and trailer to a controlled stop; Only if they fail, do you want the trailer's brakes activated. Having the trailer slam on its brakes, full-force, while its still connected to your truck, could really ruin your day.
as such, the break-away cable should be longer than anything else, and it should be connected to something other than the hitch or receiver. (if the cable is connected to any part of the hitch system, and it falls out, the pin won't pull, and the trailer will go on its merry way). I replaced one license plate bolt on my truck w/ an eye-bolt, to which I attach the break-away cable.

Now step back a second and rethink your position.

You are going down the road and the ball or hitch breaks and the trailer tongue drops down on the crossed chains and most likely starts to drag on the ground. The breakaway cable is still not released. The sudden crashing sound would cause the average human to hit the brakes causing the trailer to come smashing into the rear of the TV.

Now if the cable had pulled the pin you would still have the trailer tongue dragging on the ground and the trailer attempting to stopp the combination before you hit the brakes and ruin both the front of the trailer and the rear of the truck.

Luckily I had just stopped to rest after a 5 hour run when the head shattered and dropped. Had that happened while towing I would not have wanted that 8,500 lbs freewheeling behind me.

[richinny]

one thing that bothers me about the break away switch is that it applies full power to the brakes. in most cases that results in the wheels locking up. has anyone ever seen any system that would provide a fast stop without smoking the tires. i guess anti lock brakes for trailers is a long way in the future.

i'd sure love to see a test where a trailer (hopefully not an airstream) gets cut free and full brakes are applied.

[HowieE]

Originally Posted by 84Sovereign

What do you clip the other end of the break away cable to? (Not sure if this is correct, but I clip mine to the factory loop on my GM hitch designed for safety chains )

I use a locking pin and place the loop on the pin before putting the lock on the pin. Again this is essentially a center line location, thus not effected by turning

[moosetags]

First off cytaylor, welcome to the Forums. We're glad to have you with us.

As to the emergency brake switch on Lucy, I test it on a regular basis. I do it quick and dirty. Without the trailer plugged into the tow vehicle, I pull the cable, walk back near Lucy's wheels on each side and if I hear a "hum", I consider it working.

Brian

[Chuck]

Originally Posted by HowieE

Now step back a second and rethink your position.

You are going down the road and the ball or hitch breaks and the trailer tongue drops down on the crossed chains and most likely starts to drag on the ground.

um...no, the crossed chains are there to prevent just that.

Originally Posted by HowieE

The breakaway cable is still not released. The sudden crashing sound would cause the average human to hit the brakes causing the trailer to come smashing into the rear of the TV.

no, again. The umbilical is still connected in this scenario, and the trailer's brakes would apply with the TV's. If the brakes are properly adjusted, the trailer shouldn't be smashing into anything.

Originally Posted by HowieE

Now if the cable had pulled the pin you would still have the trailer tongue dragging on the ground and the trailer attempting to stopp the combination before you hit the brakes and ruin both the front of the trailer and the rear of the truck.

quite possibly causing a loss of control, as the brakes are applied full-force, at worst, or at best, bringing you to a stop in a very bad place, like the center lane of a super highway...

Originally Posted by HowieE

Luckily I had just stopped to rest after a 5 hour run when the head shattered and dropped. Had that happened while towing I would not have wanted that 8,500 lbs freewheeling behind me.

it wouldn't have, so long as the break-away cable wasn't attached to the same piece.

[nate3172]

I would have to say I agree with Chuck. I have been in the commercial truck repair business for alot of years and have seen ALL sides of the coin when it comes to trailers and such breaking away from the tv. The breakaway switch is designed as a last resort in case the safety chains also fail. Here is one scenario why (which I have seen the aftermath of). If the trailer comes off or dislodged from the hitch on the tv and the trailer's brakes are not adjusted perfectly evenly, which is almost impossible to achieve, when the trailers brakes apply from the brakeaway switch the trailer is undoubtedly not going to stop in a straight path. When this happens you do not want to be tied to the trailer in anyway because it could cause a rollover with the tv and also could be potentially more dangerous to you, your passengers and others on the road. The tv's brake controller should still be functional and you could manually apply the trailer brakes with the slider to "finesse" the trailer to a stop.

[tallytwo1994]

Originally Posted by nate3172

The breakaway switch is designed as a last resort in case the safety chains also fail...........If the trailer comes off or dislodged from the hitch on the tv and the trailer's brakes are not adjusted perfectly evenly, which is almost impossible to achieve, when the trailers brakes apply from the brakeaway switch the trailer is undoubtedly not going to stop in a straight path. When this happens you do not want to be tied to the trailer in anyway because it could cause a rollover with the tv and also could be potentially more dangerous to you, your passengers and others on the road.

That's pretty convincing. I've also learned that I haven't given this anywhere near enough thought. All possible scenarios are pretty scary and not something pleasant to think about. But one must.

Thanks for the discussion above
Carol

[jsutro]

Excellent examination and discussion of the topic. There are a lot of theoretical givens, like the crossed chains will support the trailer tongue, the umbilical is still intact and the driver has control of the trailer brakes, or perhaps not, et al. It all depends upon what component(s) actually fail. When the "breakaway" switch activates the brakes, the trailer has already broken loose from the TV, whether completely or partly, and all the chains, wires and cables are a tangled mess of stresses and sparks. Stopping the trailer is legally deemed to be safer than letting it continue to run free. jsutro

[Dakota's Dad]

Dang.. I need to fix my brakes.