Wiring electric brakes on trailer
LEW1
Join Date: Feb 2002 Posts: 2 camp verde az |
2002-02-21 35776
My trailer's electric brakes need to be re-wired. Since the electro-magnets on the brakes each have two wires am I correct in assuming that one goes to the brake controler on the tow vehicle and the other to ground? Does it matter which one is grounded? If so, how do I determine which goes to ground? Thanks for any advice/information.
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Wiring electric brakes on trailer
Charlie Iliff
Join Date: Posts: 1 |
2002-02-21 35777
It doesn't matter which wire goes to ground. It is best, however, not to trust the chassis ground, but run two heavy wires to each brake, all the way from the tow vehicle. The ground wires can be grounded to the chassis, as well. A common problem with trailer wiring, and brakes particularly, is the ground on your tow vevicle. Most trailer connections have a ground wire to the chassis of the truck. A better setup, again, is a heavy wire from the negative pole of the battery to the trailer connector. Bad grounds masquerade as all sorts of other problems, so good redundant grounds often save hours of diagnosis.
Good luck.
Charlie Iliff ....
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Wiring electric brakes on trailer
german
Join Date: May 2004 Posts: 2 Grass Valley,CA |
2004-05-30 87300
As long as we are on the subject of the electromagnets, can one test them by applying 12 V DC to one wire, and ground to the other, then simply check for a magnetic attraction betweeen the magnet and the drum? I have "inhetited" a horse trailer and have been told the electric brakes don't work. I don't have a controler yet, the wiring was a mess, but I have that sorted out. Am in the process of packing wheel bvearings and would like to verify the brrakes do work.
Thanks for any hekp you can offer
German ....
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Wiring electric brakes on trailer
Murf
Join Date: Dec 1999 Posts: 7249 Toronto Area, Ontario, Canada Pics |
2004-05-31 87323
German, usually when electric brakes don't work it is for a simple reason.
Probably the most common reason is wear. The electromagnet is embedded in a steel cup filled with friction material, when the power is aplied the magnet sticks to the drum and is dragged along, mechanically applying the brakes. When the magnet assembly wears down it eventually gets to the point where the coil gets shorted straight to the drum. This means the magnet loses its 'sticking' power.
Next is rust. Electric brakes develop very little application power compared to other types, like hydraulic. Disassemble, clean and reassemble usually fixes this problem.
Last is wiring. Broken or frayed wires, poor or no ground can all mean no brakes either. Make sure all grounds are solid and making good circuits.
As for testing, an ohm meter will tell you if the magnet is making a good circuit or not. A battery charger will definitely actuate the magnets. If you can jack the trailer up, apply the charger to the brake circuit and try spinning the wheels. Even if you cant jack it up, a charger on the circuit will create a deep hum that you can hear by leaning down next to a wheel.
Best of luck. ....
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