Trailer brake troubleshooting.

[OT]

Okay guys, here's the problem.

The trailer brakes used to work fine. A couple of weeks ago the electrical hook-up on the receiver of my pickup was knocked off while traversing a muddy rutted diveway. It was left hanging but no wires were ripped out and nothing else looked broken. I welded the outlet back onto the receiver and everything looks normal. The problem is that now the trailer brakes don't work. The in-cab controller reads just like as if the brakes were working correctly but nothing happens back at the trailer, no clicks, no squeals, no noises, no brakes. One odd thing that happens when the brakes are applied is that the side marker lights light up and go from dim to bright as the numbers on the controller go up.

Could it be coincidence and the brakes are just messed up or do you think it's electrical? The last time I used the trailer and the brakes worked, was in October to and from Moab and it's been sitting since.

Any ideas?

Edit: When the brakes are pressed (sitting in the driveway), there is a quiet mid range pitched hum coming from the rear trailer axle (the one with the brakes).

 

[Rev Den]

Check your grounds.

HTH

Rev

 

[OT]

Is it possible that the insides are too dusty? Is it necessary to pull them apart occaisionally and clean them?

The grounds are through the factory wiring and nothing's diconnected, so I don't think there would be a problem there. Why would the trailer lights slowly light up with the numbers on the brake controller but the brakes not activate? It's like the magnets aren't energizing. What's the buzzing sound that I heard? Is it the magnets shorting out on the drums and sending the electricity through the ground of the trailer and backfeeding into the lights?

 

[old_man]

As for the grounds, just run a wire from the frame on the truck to the frame on the trailer. Double check all the fuses. Some vehicles have seperate fuses for the trailer lights. Is this a trailer that has a seperate battery? If so, try charging the battery.

 

[Rev Den]

When trailer lights or brakes don't seem to make sense, grounding is alway the first thing to check.

Agree with the old one...run a seperate ground and recheck. Also get your multitester out and start checking voltages and currents.

HTH

Rev

 

[dyna]

Does your brake controller buzz at all now? sounds like you have a ground issue. I actually had the set screw for the brakes on a 6 pin female end short out to the plug housing and cause no brakes. what a PITA it was to find. I ended up moving the brake wire to the center pin.

 

[OT]

Does your brake controller buzz at all now? sounds like you have a ground issue. I actually had the set screw for the brakes on a 6 pin female end short out to the plug housing and cause no brakes. what a PITA it was to find. I ended up moving the brake wire to the center pin.

Only the drums buzz. I'm gonna run through all the grounds and figure out what's up tomorrow.

 

[XJJPR]

It sounds like the running lights and the brake power are touching each other in some way. Especially with what you say about them and the controller.

The brake drums should hum sitting in the driveway not moving with the brakes applied. No humming with the brakes off.

But I'll say the same as everyone else, check the ground. Some of the grounds off the receive are short and just connect to a close screw. If this was all hanging that ground might have been broken.

Also take the thing apart to see if any of the wires inside got twisted and are now touching.

HTH

hinkley

 

[OT]

Well, the grounds were all solid and I ran a seperate ground, which proved nothing, so I checked continuity through the outlet on the receiver. Lo and behold, no go. I then pulled the outlet out of the bracket and took it apart. The connectors had the green crust of crap on them and needed cleaning. After I cleaned them I gave 'em a coating of dielectric grease and reinstalled it all.

Now the brakes work again. Thanks for the help, guys.

 

[Goatman]

Just a note on trailer brakes, since we're on the subject. I wore my trailers brakes out in one year, and it was because I had the controller set too high. I didn't really understand how the trailer brakes worked, but I found out. They are electric brakes, and are actuated by electromagnets against the backing plates (hence the humming), and the magnets gradually wear out just like the shoes do. On mine, the magnets were worn down enough that they didn't get a good pull against the backing plates, so the brakes didn't work well, like they were badly out of adjustment.

I'm sure I did the most wear on one sightseeing trip on the way to the Rubicon last summer, I used the brakes more in one long downhill from a high mountain pass than I would in 5 trips to JV. Now I keep my controller set very light.

 

[OT]

Just a note on trailer brakes, since we're on the subject. I wore my trailers brakes out in one year, and it was because I had the controller set too high. I didn't really understand how the trailer brakes worked, but I found out. They are electric brakes, and are actuated by electromagnets against the backing plates (hence the humming), and the magnets gradually wear out just like the shoes do. On mine, the magnets were worn down enough that they didn't get a good pull against the backing plates, so the brakes didn't work well, like they were badly out of adjustment.

I'm sure I did the most wear on one sightseeing trip on the way to the Rubicon last summer, I used the brakes more in one long downhill from a high mountain pass than I would in 5 trips to JV. Now I keep my controller set very light.

My controller adjusts from 0-13 and I have it set on 7. This stops the whole rig very well when the button is pushed. I figure it's just right. What's yours set on?