help brakes

[DOCTOR-MX]

I have a question I put a DrawTite 2-4 Brake Electronic Brake Controller - Time Delayed and the trailer brakes doesn’t work,( I own an old travel trailer ´80, Bravo (brand), made in Ciudad Juarez Mex. about 29-30f. and 6000 lbs, two axel). I checked all wiring (7 pin connector), and every thing works fine, but no brakes. I have current in the connector (blue wire) and following the wire there are continuity till the brakes, but after the magnet also I have power (with a light tester), is that correct?, because I thought one wire goes to ground and the other comes with de current, wrigth?. With the other truck (82 Dodge 360) I used a Tekonsha hydraulic type, and the brakes works fine, now I change it for a 96 F250 PSD and I have the problem. I have read that unless you go more than 10-15 miles/hour (maybe this weekend I’ll try but in the meantime) , it will work, is that correct? or what is wrong? How can I test the electro-magnets and to know if they are fried?

Thanks for all the inputs.

[uwe]

Originally Posted by DOCTOR-MX

How can I test the electro-magnets and to know if they are fried?

Thanks for all the inputs.

Put 12V power straight to the magnets. You should hear a clunk and/or a hum from inside the brake drum.
Also, make sure your negative side is solid ( ground)

[DOCTOR-MX]

Uwe, thanks for your answer, I already put 12V straight to the magnets and not any noise and with the axe in block, the wheel spins freely. I´m goning to check the ground. any other idea?


thanks again

[uwe]

Originally Posted by DOCTOR-MX

Uwe, thanks for your answer, I already put 12V straight to the magnets and not any noise and with the axe in block, the wheel spins freely. I´m goning to check the ground. any other idea?


thanks again

Time to pull the drums and inspect the wiring and magnets. You might try and read resistance for each individual magnet, and make sure you don't have a wiring break somewhere, or a corroded ground terminal, hard to say without actually being there....
Remember, it takes hot AND ground to make things work.

[Goin camping]

Dr. Mx. Can you pull the drum and post some pictures of the brakes, wires etc?

[DOCTOR-MX]

I will, but first I´m going to check the groun, but now it´s rainning a lot here in my town, so I have to wait to better weather. Thanks anyway.

[DOCTOR-MX]

Another questions: I´m planning to work tomorrow with my trailer brakes, (if it doesn´t rain)
1.- The magnets has 2 wires, is one of them specific for hot (12V) and the other for ground, or it doesn´t matter which one you use? are there any mark (+ or -) on the magnet or an specific position (central or periferic or something like that)??

2.- The magnets have to show continuity between the wires with the tester?

Thnx for the inputs

[uwe]

Originally Posted by DOCTOR-MX

Another questions: I´m planning to work tomorrow with my trailer brakes, (if it doesn´t rain)
1.- The magnets has 2 wires, is one of them specific for hot (12V) and the other for ground, or it doesn´t matter which one you use? are there any mark (+ or -) on the magnet or an specific position (central or periferic or something like that)??

The wires coming off the magnets can be connected either way, as long as there is no short. Not speficic to + or -

Originally Posted by DOCTOR-MX

2.- The magnets have to show continuity between the wires with the tester?

Thnx for the inputs

The magnet coil must show resistance. I do not know the actual value off hand, but there should be some Ohm reading on your meter, neither indefinite, nor "0".

[DOCTOR-MX]

First thanks again uwe.

I worked all yesterday morning checking the wires under the TT, and I founded that the problem was the ground wire, in some part was interrupted. So I put a new one and every thing is working OK. I can hear the "buzz" of the magnets and the wheels blocks in both sides when foot or manual break action.

So in resume, as several of you mentioned and which I founded in the forum searching for electric brakes, the main problem is GROUND.

Maybe next week I´ll try it on the street.

Thank a lot to all of you and the wonderful AS forums.

My best regards. JOSE A.

[DOCTOR-MX]

I read that the resistance is 3.2 ohms.of the magnets.