I have a problem with my trailer brakes but I can't figure out if it's in the ABS of the truck, the brake controller or something in the trailer.

Truck and Trailer Set Up:

Truck '07 Ford F-350 with 12' Flatbed 6.0 Diesel 5 Speed Auto with Tow Command System

Trailer: 18' Pressure Washing Trailer with 2 7,000 Dexter Axles with brakes on both axles.

The Problem: The trailer brakes seem to work great but when I get 1/2 down on the pedal and the lights on the controller go past 1/2 way it seems like someone cuts the brake wires going to the trailer and the trailer brakes release. Then after that the trailer fault light comes on in the dash. Going down hills and putting little pressure on the brakes everything works fine. I slide the brake controller over manually on a stop and the trailer brakes activate. I have the gain set at 5.0 but even set at 6.0 it does the same thing.

I have an appointment set for Thursday at the dealer. I have checked the trailer 100% and can't find anything wrong with the trailer. Keep in mind I pull this trailer 95% of the time with my truck.

Anyone have any suggestions as to what may be going wrong? It only started doing this a few days ago.

Thanks
Vince

 

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BEFORE ANYTHING ELSE HAPPENS I WANT YOU TO DO ONE THING PLEASE:

Take a very hard look at all the GROUND POINTS, CONNECTORS, AND WIRES (that have anything to do with establishing a common ground between the truck and trailer).

It's a true statement that 99% of all trailer problems are caused by a bad ground... Logically therefore - you want to make sure that the ground return path for all that stuff is copacetic and cool.

*NO rust
*NO funky connectors that may or may not be bad
*NO messed up screws going into the frame(s)
*NO "F'd up" splices
*NO cruddy battery connections

~You should be able to touch a ground point on the truck and trailer when they are hooked up with a meter reading the low scale of ohms (resistance) and read less than one. It should be zero, if it isn't - that could be the cause!

In FACT (What is it all those money grubbing revivalists say? Oh yeah: "I TELL YOU THIS IN LOVE!") DO NOT hook the trailer up on the ball. Seriously.

Back up to it close enough to plug in the trailer connection - but without the truck touching the trailer and then test it.

The reason is that your ground in the wiring may be bad, and the only ground may be through the trailer ball.

THAT is a bad situation, and this is the one way to tell. Your main ground has GOT TO BE through the wires. It's the only way your truck can maintain a constant connection to the trailers electrical system.

 

Did this setup work before and now has a problem or has it always had this problem?

The problem sounds like the brake acutators are drawing more current than the controller can supply.

If the system used to work, I would suspect a wiring problem -- starting with checking the grounds, then looking for corrosion at each of the connectors involved, finally checking the wiring itself if nothing else is found first.

If the system has never worked, first check the specifications for the actuators and the controller to make sure that the controller is capable of providing the current for the actuators. If the specs are ok, then you're back to checking the wiring.

 

I am haveing the same problem with Mine.What I found out I pulled the tow command from the dash.Measured voltage from white wire(grd)to blue wire (brake)0 volts slide the slide bar 10.2 volts each gain should be the volts.Hit the brake pedal w/slide bar off 1,56 volts.My problem is the foot feed power isn,t getting there going to dealer in PM.

 

There should be an adjuster on the controller to change the amount of volts applied under different conditions. (Usually a thumbwheel)

In town you want more force - on the highway you want less. Same also with hills going up or down...

The majority of controllers have a simple on/off switch at the brakes, it doesn't sense how deep you have your foot in it to stop. Better controllers DO HAVE "applied force" sensing, but are more expensive.

 

Only the new integrated OEM controllers sense how much you are pressing the brake. Older OEM and all aftermarket controllers have to use another method unless it has a connection to the brake hydraulics.

I understand that some controllers simply increase their output based on how long the brake is applied (generally reaching full braking rather quickly) but most controllers rely on some sort of inertia sensing system that tries to sense how much the vehicle is slowing (the more you are slowing, the harder it thinks you are braking and the more output it provides). For cheaper controllers the inertia sensor is simply a pendulum (which, of course, doesn't work quite right if you are going up or down a steep hill) better controllers use fancier inertia sensor systems.

 

I explained to a service manager what My problem was He had Me show His electrial Man the test I done.Pulled tow module white to red with slide good hit pedal 1.5 volts.He went got a tow module from a 250 same year plugged it in good voltage with pedal and slide10.5.Last two dealers would not let Me show them above the learning curve I guess.

 

If it isn't in his computer, he don't know what to do. Give him a VOM and he don't have a clue on how to work it!!! Typical of a NEW mech.

 

I'm confused. I think I have a similar problem. I have a 2007 F250 with the tow package and factory in-dash brake controller. For some time now, when I start the truck (with the 5th wheel hitched up) the unit momentarily shows my preprogrammed setting of 8, then after a second or two, the 8 becomes a 10. When braking out on the highway, it doesn't feel like I'm getting any trailer braking at all. With my foot on the brake, slowing down for an off ramp for example, I can reach down and manually apply some trailer brakes and they seem to work fine.

I have metered the female plug in the bed of the truck and discovered a similar situation as the one above. I get only 1.2 volts when the brake pedal is pressed hard and 11.2 volts when the controller's slide is manually activated. Do I need to replace the conrtoller itself or is it something else?

I just got the truck back from Mike Davidson Ford in Jacksonville where they tried to identify the problem. They ended up taking my factory 7-way connecter at the bumper out of the loop and rewiring the connecter in the bed. For this they charged me $376!!! And the problem is still not fixed!!!

HELP!!!!!!!

Thanks!

 

TBC is a plug and play, did they try to swap is and see if a new one had a issue? I think that it is the control module.

It does not want to work normally, with the ABS. When you do it manually then you are by passing the ABS.

 

No, they didn't try that. They put a portable computer looking device plugged into an outlet below my dash and took several readings. Then they checked the twist caps on the connections in the front of my trailer to be sure they were good and plugged in a trailer emulator in the bed with no success. They seem to be convinced it's my trailer, but how could that be when I can activate the brakes manually from the controller?

I'm only here through noon on Monday. Maybe I can be there when they open and see if they will try the swap.

 

They need to test it with a known good unit.

The output is on the same line, number one. (Both from the emergency switch and the pedal activated circuits)

Also - you should be able to adjust for harder brake signal on the controller.

To me it sounds like a bad controller. Any decent controller hooked up right should be adjustable so that when you stab the brakes going slow the TRAILER will yank the truck to a stop! That's at the max setting, which you don't want set that hard normally.

 

Yup..that is the best way to confirm. Only if you had a message of TBC fault in the message center will the PCM throw a code. It could still be bad.