Cruise control went PSYCHO!

[LDechaine]

Hey all!



So I was minding my own business, "clacking" down the freeway as I like to call it, with cruise control set at about 65mph. Suddenly without warning the pedal went to the floor/full throttle (heart has resumed beating now, FYI). I turned the cruise control to "off" and the pedal came back up. After a few minutes and making sure there were no other vehicles in my path, I turned the cruise control back on for a few seconds, and after nothing odd happened, I hit the "Set" button again. Away we went! Full throttle, pedal on the floor. I have tried the cruise a few more times (after letting the truck sit, etc) and still the same full-throttle experience.



I have checked the continuity of the cruise control switches and everything seems to be working as advertised. I have also noticed that since this happened, that after my truck sits (engine off) for any length of time, that my brake pedal is very still and I appear to have lost vacuum in the brake system. Once I start the engine, everything resumes to normal.



Any idea where my problem may lie? Any help would be very much appreciated! Thanks!

 

[LDechaine]

Anyone, anyone?

 

[Philip]

See if can find a used cruise cotrol head assy to do some testing with. I think the electronic's has died in yours.

 

[LDechaine]

Thanks very much for the reply Philip! That is my fear too, as it seems everything else works properly. The brake pedal issue was the only thing that made me think perhaps it was vacuum-related (check-valve or something).

 

[poor]

I'm having the same affect with my cruise control-set it and away it goes to full throttle! Let me know when you figure it out! Thanks!

 

[gmsboss1]

I had this exact problem and it turned out to be the speedo pickup. It failed and the computer told the cruise control that the truck was slowing down so, of course, it accelerated! Other symptoms were that the speedometer was erratic and the autotrans began shifting erratically, too. Hope this is your problem, too, because it is about the cheapest thing that could go wrong to fix... ...