cruise control stuck on - please help

[JPW1]

I have a 1993 Ford Explorer XLT.

When I turn the cruise control on and set the speed it works fine and seems to disengage when I push on the brake. But as soon as I release the brake, it tries to resume to the previous set speed.

That really is scary when you slow down behind a car, release the brake and the explorer takes off trying to resume the previous speed.

So for now, I drive around with the CC off.

Thanks for your help.

 

[F150hybred]

Replace the brake light switch located under the dash attached to the brake pedal.

I bet you have no brake lights, eh?

 

[MrShorty]

As posted, check the brake light (BOO for brake on off) switch, or the wiring between the BOO switch and the cruise control. Your symptoms suggest that the cruise control is not seeing you press the brake.

 

[JPW1]

Brake light switch was replaced and we do have brake lights. I will check the wire between the BOO and cruise control - then let you know.

Note that the cruise seems to shut off when I push on the brake pedal, so its not fighting me when I brake. But when I release the pedal it tries to come back on to the set speed. Like the CC gets the message, but then forgets?

It did work for a short time after we reworked a few of the vacume lines. Wondering if it could be vacume related, what do you think?

 

[The Yellow One]

Same issue...made worse

I has the same issue with the CC not shutting off when I pushed the brake. Ended up finding out I needed a new Boo. I replaced the switch and now I have no CC what so ever. MY next move is to replace the CC (plug?) behind the master cylinder.

There has been multiple threads on CC issues. Some have said that plug behind the master cylinder is dealer only. I actually found it cheaper on rockauto.com.

 

[MrShorty]

Note that the cruise seems to shut off when I push on the brake pedal, so its not fighting me when I brake. But when I release the pedal it tries to come back on to the set speed. Like the CC gets the message, but then forgets?

This is due to the brake "dump" valve on the brake pedal. It is a mechanical "failsafe" valve that releases the vacuum used to drive the servo. This dump valve is completely independent of the electronics, which is why the cruise comes back on after you release the brake.

 

[jd4242]

This is due to the brake "dump" valve on the brake pedal. It is a mechanical "failsafe" valve that releases the vacuum used to drive the servo. This dump valve is completely independent of the electronics, which is why the cruise comes back on after you release the brake.

x2

 

[Delta_1980]

so did you fix the problem?

 

[jg09]

My first explorer had this problem, it wasn't sensing when the brakes were being applied. I could use cruise control to hold brake stand burnouts lol

 

[impetie]

My 1994 Explorer sport did the same thing when my sister jack-knifed the trailer she was trying to back up and pinched the trailer harness and blew the brake light fuse. I could set the cruise control but could not cancel it by applying the brakes. I had to cancel it by shutting it off.... That's when I discovered I had no brake lights. Replacing the fuse returned both the brake lights and cruise cancelling ability.