Trailer brake controller

Before I go buy a new one,I'll give this one try. Trouble is,I don't know electronics from a bale of hay and I don't have enough info for anybody to go on.

I don't know the brand,so that's probably the end of it,but there's a controller in my 85 Ford F250 that was in the truck when I bought it in 90. It has a wet line from the master cylinder to activate it. It had a short lever on it too,has a red light that comes on when it's activated. There's a knob on the underside that I always thought adjusted the sensitivity from the pedal,but now I don't know. Is there a possibility that a controller that old would change the amount of current that goes to the trailer with that knob? I don't know,amperage,ohms,whatever?

The last few times I used the trailer the brakes were getting worse. Monday they didn't work at all as far as being able to feel them even start to drag on the trailer when I activated them with the lever. I tried to adjust them and all the adjusters were froze up. I took a hub off to free one up and the face fell off the shoe. Went to town,ordered new ones,changed them on all 4 wheels,freed up all the adjusters. I got them all put in. I can hear them click inside the drums,I ALMOST can't turn the wheels by hand when somebody activates the controller,but if I really horse on the wheels,I can turn them.

Still,no drag,won't even slide a single wheel in the dirt. I've been under that thing at least six times tightening the adjusters. If I hold the lever for a quarter mile or so,the drums get hot,but no stop.

I've turned that knob until evidently I've turned it all the way off inside somehow,because it just keeps going one way but won't turn the other way now.

So is it possible that a controller that old is sensitive to current and just needs to be replaced or is the problem in the brakes on the trailer?

See if the brakes will lock up tighter by using a 12v battery charger and a small screwdriver stuck in the plug of the trailer.

Make sure you are grounded good.

Gary

That is the best kind of controller and one you can't use on newer trucks. Not likely your problem. I would say you have a wiring problem in the trailer. I would start in the plug and work back making sure the ground is good.

That thought crossed my mind. Does anybody know how many amps,or ohms,or whatever to heck should be at that pin in the female trailer plug? There's definitely power there. I checked it with a test light while the wife activated the controller. I've got the boy's multi meter here if somebody can tell me what symbol to turn the knob to.

We used those back in the 70's, they were great controllers. The way the wet line worked, the harder you pushed the brake pedal, the more current it sent to the trailer brakes. The knob adjusts the level of current so you can fine-tune the trailer brakes. I think it is a Tekonsha brand. I do know that it was a big improvement over the Kelsey-Hayes units that we had used earlier.
I was told that these wet line units are not compatable with ABS brakes, and that's why you never see them now.

OK,so if I turned that know too far and turned it right off the end,that might have stuck it at a low current so it barely works? It used to come to a stop in both directions,now it keeps going one way,won't go back the other,just like something is trying to start threading back in crooked or something. I can see a spring down in there,don't know if there's a threaded rod inside that or what? I don't see any way to take it apart.

I might be able to help you get it apart and look inside it.
Much like a laptop or tablet case and I use the same meter.
I won't have any time until Sunday though.
By the way, don't get mad at it and pitch it.
I've been looking for a wet line controller for over a year.
Still looking.
Guess if I get serious enough I'll go to a dedicated trailer place.
As far as the brakes go, a bad ground would be a likely culprit.

How about this. I just tried the battery charger trick. I hooked the negative clip right to the trailer tongue,stuck a small screwdriver in the plug,had Kim hook the positive clip to the screwdriver. Same thing happened. I heard the click,the tire was hard to turn,but I could still turn it.
Ground between the brake units in the wheels and the trailer frame? I honestly don't know if they all come to a common ground or if one side grounds somewhere and the other side somewhere else or what.

I HATE fooling with anything electrical!

I don't think your problem is electrical at all. I think you still don't have those brakes set up far enough. Turn those adjusters till you get some pretty good drag on each wheel then try the juice again. I bet it will throw you through the windshield.

Well, that pretty much eliminates the controller as the root cause.
Although it is still broken and will need to be fixed. I'm guessing it
is either at full on or full off with the wheel not turning right.
If you've got them adjusted out good and they still don't hold, I'd
still say bad ground or a bad connection in the positive wire.
If the brakes are not separately grounded, I would make them that way.
At least then when one ground wire failed you would only lose one brake.
Unless of course you lost ground to the whole trailer.

Twice today I tightened them up until I could barely budge them by hand. Expected the wheel to slide when I dropped it down and took off with it. Took it about a mile and a half,came back and did it all over again. Right now they're tight again and even using the battery charger the brakes won't completely stop them.

I'm lost.

I'm gonna go get a new plug for it in the morning. I found out there's no power to the right turn signal or 5 of the clearance lights either. I've got power to both tail lights and the left turn signal. Thinking back,Kim said the brake lights weren't working earlier today either. There's power to the pins in the truck plug. I'll cut the wires right off,skin them back and put them in a new plug and see what happens. I'm wondering if there's too much corrosion causing low power or something?

I think you need to measure your voltage at the brake; you may be losing current thru connections in the wiring on the way to the brakes from the plug if your charger is indeed puting out 12+ volts or your controler, you may not be getting it back at the brakes. Use a good volt/ohm meter. Mark

Could be the plug, sounds like a bad connection somewhere.
Light circuits are separate from brakes though, other than
the common ground.

At this point you either have a poor electrical conection or your brakes are just worn out. Did you try more than one wheel? That should help tell if it's electrical or bad brakes. Not likely that all would be so worn that they don't grab unless you do top notch maintainance and keep them adjusted well.

All new shoes. I freed up the adjusters,have tightened them up til I can hardly turn any of the wheels,still won't drag a wheel in the dirt.

How many times have you changed the brake shoes? If you are on the 3rd or 4th set you may have worn out drums. I've seen where they get so large the shoes don't reach well enough. Try putting power directly to a magnet also to eliminate any wiring issues further forward.

This is the first time I've changed them. There wasn't much more material on the new ones than there was on the old ones. The drums weren't worn at all. I just had to chip rust off behind where the shoes wear in the drums was all. And free up the adjusters of course. The trailer is a 95,so it's not like it's some old thing from the 60s or something.

I put a new plug on it this morning. The lights all work now,I got that knob to work???? in as much as I can turn it now anyway both directions. If I go all the way one way,it seems to get a little better hold. Driving slow in the driveway I can at least here them squeal when I apply them if I listen close from the cab. If I turn it the other way,nothing. I've got them so tight that when I drive slowly over a dip in the driveway,the wheels stop turning without even applying the brakes. I still think the trouble is in the controller. It's just not turning to where it has enough sensitivity.

I've parked it. Frustration has hit the boiling point. Unless somebody has an idea or I have some kind of epiphany,I'm getting a new controller.

Before you give up that controller make sure you apply 12 volts directly to both wires of the magnets to see if you get good braking then. That is a much better controller than anything you can buy today and gives more smooth stopping. Also if you have a voltage tester check the voltage to the blue wire with the lever pushed all the way. You should get full battery voltage at that point, if not, then the controller is your problem.