Truck Accelerates/Revs when I brake with Cruise Control On

[JasonAmericanBulldog]

So my truck has decided it wants to accelerate/rev-up when I go to brake with the cruise control set. It does not matter at what speed the cruise is set at. What should I be looking for? Could it be fuse related, damaged wire/harness? Certainly appreciate any help, these kind of electrical gremlins leave me clueless.

[NYC F-350]

My uneducated guess (after skim-reading the cruise control section of "the book") is that it could be a clock spring problem or a speed control deactivator switch (part of master cylinder).
Do your brake lights work properly?

[JasonAmericanBulldog]

all my lights are working. took it for a ride today and it doesnt seem to be doing the ecxact same thing. this time it isnt disengaging out of Cruise smoothly, still wanting to hold RPMs but it didnt want to rev/boost and take off like last time

[sinner6.0L]

the only thing that will make the truck re-accelerate is the resume switch. I'd be looking for a problem related to that switch possibly being stuck on

[HankY]

I have a same problem, was advised to replace the brake switch on the brake arm. I bought one and it will be put on by the guy doing my oil cooler and other stuff. Dealer told me some of the wires may break at the switch or the switch itself could fail in the cruise loop. Mine had to push extra hard to get from P to D! So will know in a week or so.

[JasonAmericanBulldog]

i'd much rather replace the speed control deactivator switch as it's cheaper then the switch in the steering wheel. i believe it may be the speed control deactivator switch as i un-clipped it today and it was moist/gooey and thinking it's seals have failed. I've read that they can cause your vehicle to catch on fire. If that doesnt fix it then I will deff look into the resume switch.

Edit: on fordparts.com there are two parts with the same name and number and point to the same thing in the diagram.
9F924 (This one has Motorcraft eblem/label)
(SW-6349)
Cruise Control Cutout Switch
6.0L; Speed control deactivation switch (Only the switch) $38.05 ($28.54) In Stock Add to cart

9F924 (this one has the Ford Genuine Parts emblem/label)
Cruise Control Cutout Switch
Redundant Speed control switch; Mounted on master cylinder $16.98 ($12.74) In Stock Add to cart

anyone know if there is a difference, if not then I'll gladly spend half as much for the "Genuine Part" over "Motorcraft"

[john3488]

Hank Y, did this fix your issue? I'm having the same issue. Cruise won't de-activate when pressing/tapping lightly on brake and also won't go from Park to Drive without pressing hard on brake.

[HankY]

yes I will go out and get the PN in a little bit. Had the switch replaced while the truck was in for R&R of oil cooler and EGR. The tech also confirmed that it sounded like the brake switch before doing it. Think the part cost around $40 some dollars is way up on the pedal.

[HankY]

The part was SW 6349 cost me $43 + tax. I did not do the install but it should be pretty easy once you get in there.

[john3488]

I replaced the brake switch ($14 at NAPA) and it cured my cruise control deactivation and also the non shifting from park to drive. The switch is located high up on the brake pedal.