brakes

[William Schelling]

When I towed my 3650-07 last week my (ABS) lite came on in the truck. Today with the trailer unhooked the ABS lite is off. If I had a problem with the trailer brakes would that make my lite come on? I only have about 3000 miles on the truck. Could I possibly have a bare wire at one of the wheels going to ground and cause that? I have the built in brake system in my Ford F250 My truck on has 9000 miles on it.

Today, I tested the brakes in the snow and the (ABS) seemed to work ok.

[Ramblin Roadrunners]

William, I manage an Aamco transmission shop. I am not a tech. When the ABS light is on, it means something in the ABS sensing unit is seeing something it doesn't like. Your brakes should still work fine-- its just your ABS portion is not working correctly. I think this is something you will have to work with Ford on. Most independent shops won't have a clue. A shop that specializes in trailors towing might be able to help. Make some calls first.
Jay D.

[HughM]

William had the same thing happen on a gas M/H I once owned. ABS would come on. When I cut the engine off and restarted it the ABS would go off. M/H was on a Ford chassis. It might come on in 100 miles or 1000 miles. Your braking will still work but you won't have ABS.
Most likely its a wheel sensor. Mine was.
I don't think its related to you being connected to a trailer.

[bsmeaton]

I've had many trailer brake wiring problems, and they all read through the message center "Trailer Disconnected" - "Trailer Fault", etc and a red trailer indicator on the controller itself. Nothing ever came through the ABS light.

If you don't have the message center (included Lariet/King Ranch), then you should only get the red trailer indicator on the controller.

The ABS should be totally separate and non-related is my opinion

[Waynem]

The ABS only apples to the tow vehicle.
My 2005 King Ranch ABS light will come on in 60+ miles. When I stop for lunch, or sometimes even shorter, when I start it, it will be on but goes out after a few hundred feet. I'm thinking wheel sensor also.

[William Schelling]

Thanks to all of you. It does sound like a sensor.

It is just curious that when I unhook the (ABS) light doen't come on again.

Would that leave a memory in the computer on the truck?

Again, when I locked up th brakes in the snow last week, they seemed to work fine.

[richfaa]

My sensors have worked fine in both my Tv's. Don't know where the sensors are located but we did note that in the school busses we drove the ABS sensor would come on occasionally in cold, freezing weather . The garage guys said it was due to them getting wet and freezing????

[Dennis Korchak]

William, I have a 2006 F350 4x4 and had the same intermittent problem. It turned out to be the VSS (vehicle speed sensor) sensor on then top of the Differential. Easy quick fix. Your truck should still be under warranty. The sensor is a magnetic type and picks up some residue form inside the differential.

[William Schelling]

Dennis, That makes a lot of sense. I will have the dealer look at that. Thanks for the info.

[Waynem]

Dennis,
Is the VSS cleanable, or does it have to be replaced?

Thanks.

[noneck]

Umm, ABS is a whole lot more complicated than that...VSS location is as described but is "Hall Effect" device and oil should not effect its sensing ring gear rotation. There are similar sensors on each of the wheels that also monitor rotation. Then there are dump valves for each brake line to release pressure on detection of skid. All this stuff feeds back to ABS controller and a scan tool can read the error code when the ABS light is active...it is not typically a stored fault.

Quite possible when towing the additional weight is changing how one of those sensors reacts.

[Waynem]

Charles,
Thanks for the information. The dealer here seems to say that there "could" be a fault stored. I disagreed with him on the ABS and decided to wait until the light comes on and then take it in to my own shop. In my case, with the 2005 F350 King Ranch, the ABS light will come on non-towing or towing after 50+ miles or more. Goes off after a short time of being stopped, or overnight.