O/T Truck Brake Switch Keeps Failing

tg in VA · Oct 12, 2014

I have a 2002 International 8100 road tractor with air brakes that I use to pull my DreamCoach horse trailer.

The horse trailer is equipped with hydraulic/electric brakes.

The International's brake switch keeps failing, causing me to have to use the under dash brake controller to apply the trailer brakes.

I have replaced the brake switch numerous times but it continues to fail with regularity.

Replacing the switch is no real chore BUT something is making it fail. I'm no mechanic but I feel sure one of you guys are smart enough to point me in the right direction.

Thanks

Scott 730 · Oct 12, 2014

Too much current load on the switch??? :?:

Billpa · Oct 12, 2014

it sounds like the brakes are energized thru the brake switch , you will need to hook up a relay in the system

notjustair · Oct 12, 2014

Where's john T when you need him? Hang on and he will have an answer. FWIW I agree that too much current is going through that switch. It is pulling all of the amps necessary for the trailer through there. If it hasn't always done this is something grounded and not blowing a fuse?

Determined · Oct 12, 2014

The brake switch on your truck sends power to the truck brake lights.
Adding the draw for the brake controller if properley wired would be minimal.
Assuming everything is wired correct then likley the brake lights on the trailer are drawing high amps and causing your problem.
You can check the brake lights on the trailer for high draw, but my guess is something is not wired right as from what you describe you are burning out switches instead of blowing fuses.

Michael Soldan · Oct 12, 2014

The only current going to the trailer brakes should be from the brake controller. As someone suggested it sounds like all the current is coming through the switch. Check the brake controller to be sure it is wired in properly. A relay switch would help solve the problem if the power is all coming through the switch

JD Seller · Oct 12, 2014

I will second Billpa. Wire a relay into the brake light circuit. That way the only amps the switch sees is the relay operating draw.

I have done this on the clearance lights on all the pickups. The extra trailer light draw would trip the fuse/breaker on the light switch. After blackout going through a narrow bridge at 1 am scaring the pants off me, I wired in a relay. It has worked well for almost ten years now.

matthies · Oct 12, 2014

I installed a couple controllers in 08 & 09 7600 Int. Workstars and used a separate switch for the controller but I can't remember if I used a relay or not. Will have to check on Tuesday when I get back to work. chris

jon f mn · Oct 12, 2014

I would check the controler eiring too,sou ds like your trying to feed the brakes through the swithch. I've wired dozens of controllers and never had that problem. You could also have a faulty controler that's shorting just enough to create heat but not enough to blow the fuse.

T in NE · Oct 12, 2014

If you've got some first-gen Cummins pick-ups like I think you've said you have, you should have the headlights on relays, too. The added draw of of the extra lights on a dually is enough to melt down headlight switches, then you add trailer lights......

Phil9N3667 · Oct 12, 2014

Sounds like the brake light switch is way over loaded. I've got a diagram somewhere left over from my days at the IH dealership. If I get a chance, I'll look at it to see what feeds brakes/lights. As Jon said, looks like the controller may be wired in correctly.

cd1 · Oct 12, 2014

The way the controller should be hooked up-

4 wires, one to good ground. one to battery + with fuse, one to trailer and the last is brake signal. If you are using the brake switch to feed signal and battery power that is your issue. The signal wire on a brake controller should not draw a measurable amount of current, I have a similar truck hooked to the normal brake light switch and it works fine, no relays.

O/T Truck Brake Switch Keeps Failing

tg in VA

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Scott 730

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Billpa

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notjustair

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Determined

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Michael Soldan

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JD Seller

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matthies

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jon f mn

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T in NE

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Phil9N3667

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cd1

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