electric trailer brake question/problem

[dondiesel444]

ok I began the wiring on the Mack so I can pull my trailer. the truck is hooked up correct. I hooked the truck wiring up but didn't have time to mess with the trailer and I had to move my machine so I did it. the way the trailer was hooked up, whenever I used the right turn signal the trailer brakes would apply, also whenever I applied the truck brakes, the trailer brakes would apply full force (this was without the brake controller even conected).

so I get home and begin to work on the trailer. the trailer was a mess so I removed all the wires at the junction box on the trailer and started over. all the lights on the trailer work now, but the brakes don't. the brake controller in the cab indicated that the brakes are working but they aren't.

there are two wires from the trailer harness to the brakes, one is ground and one is power, correct? I don't think it matters which is which, I've tried it both ways, no luck. the controller still indictes the brakes should be working. to bypass the controller and truck wiring, what I did next was hook those two wires dirctly up to a battery. I can hear a little click back at the brakes, but not the usual "HUMMMM" when they used to work.

could there be a problem with the magnets? I really don't know what else to do. thing is the trailer has 8 wheels and 8 brakes, would all the magnets go out at once? I wonder if I over loaded them when the trailer was wired incorrect, is that possible?

PLEASE HELP!

 

[Duke]

I don't think that could happen. Is there any chance that the brakes are "on" all the time where it's parked right now?

I had a asimilar problem, only to find the emergency brake cable was pulled out of the little box, causing the brakes to be "on" constantly.

Can you roll the trailer right now as she sits to make sure the brakes aren't locked?

Are you sure the (2) wires don't each control a "bank" of 4 brakes? IOW's there's 2 "hot" wires for the brakes and the ground is a totally different wire?

 

[ISurvivedNMU]

I don't knw much about the M/D trucks, but without my brake controller attached on my truck, I would never even have the trailer brakes working..... Im wondering how you are getting a signal to the trailer without the controller attached... seems odd....

 

[dondiesel444]

ISurvivedNMU-
I had a signal to the trailer w/o the brake controller b/c the wire that controls the trailer brakes was hooked to the brake light connecton to the truck, that's fixed now.

Duke-
the brakes aren't locked up, the trailer rolls freely. I also tried connecting both ot the brakes wires together, but there isn't another wire for the ground..? when I hook one wire to power and the other to ground, there is a small spark and I hear a click back by the wheels. I should've kept track of the wires before I removed them but it was such a mess, there were wires not attached that needed to be for the lights, all kinds of corroded splices, just a nightmare. it's also weird the way the lights are hooked up, but they all work and thats what matter. I just have to figure out whats wrong with these brakes....

when I got the trailer, my IH didn't even have a connector and I hooked the IH up to the way the trailer was wired. now I have hooked the Mack up correctly and the trailer was all screwed up. I don't know much about electric brakes except they are a PITA....

what a nightmare....

 

[Whit]

Some setups use the ball to ground so if you arent hooked to the ball you prolly wont get anything, a simple gator clamp jumper wire will allow you to work on the wiring without actually coupling the ball

 

[dondiesel444]

I have the truck and trailer hooked up. what I don't understand is if I supply battery power direct to the two wires I know go to the brakes, theys till don't work. I don't know if one is power, one is ground, or if they are both power, but the I don't see another ground wire. I need to know more about electric brakes, if they need both a power and ground or just a power and the ground is internal to the magnet? there are 2 wires going to each wheel, so I suppose one is power and one ground.

 

[ISurvivedNMU]

When I was working on my elec trailer brakes.... I used a battery charger... had the ground and power... and you could tell with the magnet hum and the battery charger hum when I had the right wires... It may be easier than using the power from the truck...

 

[dondiesel444]

thats what I was using, my battery jumper pack. I think I should start at a wheel and hook the pack up to it and see what happens.

if I only had the money for a trailer with air brakes.....

 

[Copper]

Pretty much all the trailers I've ever dealt with had the brake magnets grounded to the frame of the trailer without a separate ground wire all the way to the plug. Most did have a ground wire in the plug, but it just went down the harness and hooked directly to the frame at the end of the pigtail (if it didn't have one, I added one - grounding through the ball usually works, but it can be unreliable). If you can, I'd be tempted to unhook the wires on one wheel and check the magnet individually, then work your way towards the hitch.

 

[dondiesel444]

I think thats what I have to do, start at each wheel and work my way towards the hitch, too bad there are 8 wheesl....

 

[Diezel_Cowboy]

Originally posted by dondiesel444
I think thats what I have to do, start at each wheel and work my way towards the hitch, too bad there are 8 wheesl....

First of all make sure that your brake controller is rated for 8 brakes or 4 axles! There are brake controllers out there that are not made to run 4 axles. Also if your trailer has electric over hydraulic brakes you need a controller that is made to run with electric over hydraulic! I had a problem with my old brake control (tekonsha prodigy) running electric over hydraulic brakes. It would not run them. Also some trailer require a constant power wire to be hooked up, as did ours. The power is to charge the battery for the disconnect safety, but the circuit requires that power wire to be hooked up for the brakes to work!

BELIEVE me i feel for you! It has taken me a long time to figure out all of this for myself just to get my trailer brakes to work. Hope i can save you some trouble though!

 

[dondiesel444]

thanks for the help guys. my brake controller is rated for 8 wheels, it's the same controller that was in my IH that worked on this trailer before (I removed it before I sold it).

anyways I was playing with the wires today and I must have done something right b/c the brakes worked, well kinda. I had the trailer jacked off the ground to change 2 flat tires, and I hooked the wires back up for the heck of it, 1 to power 1 to ground, and I got a real good spark this time, and I went back and the wheels were locked up, well 5 of the 8 but thats all that worked before. funny thing is I don't hear the HUMMMMM of the magnets, I beleive I used to be able to hear it. I didn't tow anything yet so I don't know if they are working fully. I don't NEED the brakes when I haul my skid steer, but they are definatly mandatory when I haul the 450 around. also I know I'll be getting calls from loggers to move their equipment any time now, so hopefully I'm ready to go.

so the brakes work, for now. thanks for all the help. any more info you guys have on electric brakes in general I'd love to hear!!

 

[Ak HDM]

Don, i believe that one wire from the magnet is power or positive and the other is ground or negative.
If you get a chance go to dexteraxle.com , they have alot of info on electric brakes .


Mike

 

[dondiesel444]

thanks I'll check that out!!

 

[Duke]

Great stuff fellas. Nice job helping out.

Any news, Don? Are they working better?