Either I have a problem with my truck or there is, perhaps, a design flaw in the system. Here's what happens:

As I'm slowly braking (1 or 2 bars on the Tow Command) and usually around 20-30 mph, something jars the truck (more on that later) and the brakes feel like I'm on ice and the TC panel stops at 1-2 bars no matter how hard I push the pedal. Releasing the pedal and re-applying pressure restores normal brake pressure.

This only happens when I'm loaded - well, make that the trailer has a full load on it.

There are two things that jar the truck to cause the problem. 1 - Hitting a bump with the truck (rear axle, I believe) and, 2 - the 2nd to 1st downshift - automatic - extremely harsh at times (let me know if you have this problem).

I never get a trailer disconnect alarm. I'm confident the trailer wiring or connectors are not part of this. I suspect the ABS is causing the brake limiting, although the ABS light never comes on. With the TC being limited at the current rate (1-2 bars), I can see there is a problem.

This generally only happens when I'm in stop & go traffic or going into a toll booth. It doesn't happen all the time - only when the truck is jarred. With 44k miles on the truck, I've been trying to gather as much information as I can. I have an early '05 and have heard (here) the newer trucks have an updated TC module - but for an unrelated problem with no trailer brakes at slow speeds - something I also experience.

Anyone else notice this problem? I've mentioned this a couple of times at my dealer, but they have never heard of it.

Jim

 

Sounds like when braking & hitting a 'bump', the ABS is engaging and causing the reduced braking. My '01 F350 had a similar issue and I was told that there was no problem. I just learned to drive/stop with the problem. Still, you shouldn't HAVE to do that.

I suspect there's going to be a "re-flash" in your future.