My wife drove the truck to her mom's house yesterday morning and set the cruise at 43mph in 4th gear. She came up to a red light and tried to shut it off, but it wouldn't turn off. She tried the brakes and it wouldn't shut off. She finally took it out of gear, came to a complete stop and the RPMs were at 1800 just like they were when going 43mph. She tried to get it to quit doing that and finally the light turned green. As soon as she put it in gear, it quit. Of course she fails to mention this to me yesterday and I find out this evening.

Would that have anything to do with the Ford Dealership fix on the cruise control switch? Or just coincidence? It never did this before. Truck specs in sig. Thanks.

 

Very curious. Mine did this to me about 4 weeks ago, I got on the brakes and she just spooled the turbo I think I hit the "set" button or something, and she came out of it. I didn't give it a second thought after trying it several more tries on my way home and it was working flawlessly. I also have the "new" switch on the master cylinder. I'll be watching where this goes.

 

Is it possible the Clutch position switch is bad? Does the truck start without the clutch pedal? That should not allow cruise to engage. Additionally, there are three fail safes in the cruise cancel system. The first is the brake light switch, which cancels cruise when power goes to the brake lights. Second is the clutch switch which is 'supposed' to cancel cruise if the clutch is pushed in. Third is a brake pedal pressure switch which under pressure cancels the cruise. It may take a hard application of the brake pedal to set off the pressure switch... Those are the three areas I would look at

 

In my case, it's a slushbox. I've never had to do more than a gentle tap on my brakes before, and the time that happened, the truck literally started to spool up to fight the brakes.

 

YIKES!

Glad your wife is alright for starters, and glad that you two are alright as well... I would call the dealer and see if any of them have had anything come back to them...That scares the living hell outta me.

 

The cruise control cable could be binding in the housing.

 

Sounds like some Toyota germs got in there somehow !

Seriously though, glad everyone got out of it with no more than just a surprise!

 

Update: When she was stopped at the light, she couldn't figure out how to kick the idle back down with the clutch depressed and stomping on the brake pedal, so she put it in 1st gear and it finally kicked down to idle.

WA.Ranger, I tried to make the truck do that last night and it wouldn't. It worked flawlessly every time.

I will try to start the truck w/o depressing the clutch today.

Where is the cruise control housing? If all three switches wouldn't cut off the cruise control, I think this sounds like a good place to start, but I could be way off.

 

There is no "cruise control cable" on these trucks.

The cruise control is all done electronically in the PCM, and there is no mechanical "linkage" at all.

Pop

 

Ok I'm way off.

How do you diagnose the switches? Ohm test each one?

 

I would replace the pressure switch on the master cylinder regardless of what you find.
The diaphram might be leaking internally and hydrolocking the switch.
Seen that sort of thing before for MANY years on hydraulic brake light switches.

 

another place to look is under the horn/airbag housing for zip ties shorting out the wiring to the steering wheel. the ECM seems to get confused as to what it should do with multiple inputs. Mine used to honk the horn when it engaged and turn left for disengage.

 

Maybe dirt or dust under the cruise on and off buttons., had to say it, wouldn't hurt using some compressed air and blowing in between the cracks.. but what do I know. Glad to hear no one got hurt..

 

Two years ago. I was on the thruway. Went to get off on the ramp.. hit the brake/hit the off.. Nothing. Kept on chugging. I proceeded on the thruway trying to get it off Cruise.. brake mashing and Off button pounding for 5 more miles.. Then it went off.. I never could get it to repeat. Always been a mystery to me...

https://www.ford-trucks.com/forums/7...ing-ideas.html

 

Master cylinder pressure switch... Is that what they jury-rigged at the dealership?