Emergency Brakes no longer working?

[LivingInBeauty]

We just noticed the brakes do not lock or even engage when we pull out the emergency brake pin and nothing happens.

We assume it could be many things, but we thought we would start here by asking some of the probable causes.

Thanks!

Jim

[RedCelicaTRD]

The contacts in the switch can build up corrosion and should be cleaned every few months with contact cleaner spray. I recently replaced the switch due to mine being rusty and not working. About $30 from tractor supply and just had to crimp two wires.

[Wazbro]

If your emergency brake switch is original on your 2001 trailer, it is way past the life expectancy for that switch.

Other things to check are that power is getting to and from the switch and then to the brakes.

[LivingInBeauty]

We do have a new switch, bought May 2024.

I checked the connections as far as I can, but the wires go into the frame within 10 inches of the switch, so I can't follow where they go.

When I pull out the pin and walk to the brakes, I hear nothing, but when we are driving and I pinch the brake levers on the trucks dashboard, we can feel the brakes engaging.

Not sure my next step.

[RedCelicaTRD]

The switch gets power from the dc distribution box inside the Airstream. You can use a volt meter and a needle to check that the switch has power. Stab the needle into the wire and use a volt meter to check for voltage. The needle is now “hot” so don’t let it bump anything. With the “key” removed from the switch you should have voltage on both wires. If the switch is not working you will only have voltage on one wire. If the little breaker in the dc distribution has failed, or the wire is cut somewhere, you won’t have power on either.

Use a dab of silicone to seal the needle whole in the wire insulation to prevent corrosion from water getting in.

[tjdonahoe]

Have to be moving to work

[richard5933]

Originally Posted by LivingInBeauty

We do have a new switch, bought May 2024.

I checked the connections as far as I can, but the wires go into the frame within 10 inches of the switch, so I can't follow where they go.

When I pull out the pin and walk to the brakes, I hear nothing, but when we are driving and I pinch the brake levers on the trucks dashboard, we can feel the brakes engaging.

Not sure my next step.

The wires go into the frame through a hole, and if you slide underneath the front of the chassis you'll likely find another hole where they come out before entering the trailer.

But, if you have 10 inches of wire then you have more than enough to replace the switch. Every one I've seen is replaced by clipping the old wires close to the old switch and then using butt connectors to join the wires on the new switch to the ends of the wires left after snipping off the old switch. Doesn't matter which wire is which when you reconnect - this is a simple on/off switch with no polarity.

In general, these switches are not weatherproof and after a few years build up enough dirt and corrosion to stop them from working. Also, the mechanism inside the switch is simply two pieces of metal bent so that they make contact, and the pin is in there to keep them apart till it is pulled out. The metal can fatigue over time which means they don't push together so firmly when the pin is pulled.

If you replace the switch and the e-brakes are still not functioning you'll have to dig deeper.

One important thing to remember is that you must have a charged battery for the e-brake to function. If the pin is pulled while you are driving, it's because the tow vehicle and the trailer have separated. There is no longer 12v power flowing from the tow vehicle and the e-brakes rely solely on the trailer's battery to engage.

If you're trying to test the e-brakes when you're not hitched up and have power to the 7-wire harness you must have a charged battery in the trailer with power flowing to the e-brake circuit.

If the battery is in place and charged, check to see if you have 12v power in one of the leads going to the switch. If not, then work backwards into the trailer to see where the break in the line is.

Originally Posted by tjdonahoe

Have to be moving to work

Still should be able to hear/feel the magnets moving.

[lovemorels]

What kind of oil would one use on the maintenance of the emergency pin brake?

[bel73]

Use Corrosion X on the brake pin. Also use it on the 7 pin connector.

[Mollysdad]

The breakaway switch basically shorts the two wires coming out of the little switch. The cable/plug just holds the wires apart in normal use. When you pull the plug you should hear a click. Don't leave the plug out for long since it's sending 12v. directly to the brakes.
(Okay, I've oversimplified the function but the concept is valid.)

[richard5933]

Originally Posted by lovemorels

What kind of oil would one use on the maintenance of the emergency pin brake?

On the plastic pin itself - none.

On the metal terminal springs inside the switch? You can spray something like DeOxit or any other corrosion preventative spray which still allows for electrical contacts to make a good connection.

[OCRV]

The electric brakes do not engage unless the trailer is moving. The magnet will be charged but not likely to make any noticeable noise. The best way to test the emergency switch is to hitch up, pull it out and attempt to drive forward a bit. The brakes should fully engage and lock up the trailer wheels. Only leave the switch pulled out for a very short amount of time as it sends full power to the brakes and can heat up.