Cruise control fails to cancel
 

My cruise (non resume early factory 77ish) worked fine for about two hours on the highway. Then upon application of the brake it seemed to cancel but lifting the brake, the cruise reapplied by itself. Something prevented the cruise to cancel. Pushing the on/off switch (deep push to position 2) also shut off the cruise but the switch had to be held in. What's wrong?

Re: Cruise control fails to cancel
 

So I drove the same 300 km today and at first the cruise worked fine, then it wouldn't disengage without the indicator button being pushed but by the time I arrived at home it was disengaging from the brake pedal as it should. The Cruise transducer has a foamy in its base to filter air that moves through the unit so maybe they can get dirty? Anybody have a clue as to servicing the transducer. The web seems pretty thin on this info. Anybody take one of these apart???

Re: Cruise control fails to cancel
 

There used to be a PDF writeup on a UK college student web page but it doesn't seem to exist anymore. If anyone has it a copy for the manuals page would be appreciated.
The Cruisemaster Service Training Textbook I scanned is in my manuals post.

Re: Cruise control fails to cancel
 

I appreciate you posting these manuals and thank you for it. However, the cruisemaster manual doesn't have an in depth trouble shooting section. I have been reluctant to buy a rebuild transducer but I will try and find one. I need to find a suitable candidate for an experimental disassembly.

Re: Cruise control fails to cancel
 

From the 77 service manual:

Re: Cruise control fails to cancel
 

And this:

Re: Cruise control fails to cancel
 

The 79 manual has a very good troubleshooting section too.
IIRC at least one of the 68-72 manuals has a fairly serious section on the Cruisemaster system as well... 67 pre-dates cruise control in the trucks.

Re: Cruise control fails to cancel
 

I appreciate your help and thank you. Today my cruise worked fine. Go figure. I am planning a big trek to Sacramento in Sept to the C10 club inaugral Intervention. Its 2200 km each way and cruise has to work. I researched the local auto parts stores and searched the internet and I cannot find a rebuilt unit. There just not available in Canada and perhaps scarce in the US. I may call O'Reillys (or somebody) and maybe I can pick up a unit in Spokane on my way through. For the moment mine works and disengages okay. Perhaps the dirt that was contained within it has been sucked out by vacuum and it may operate for awhile.