Cruise control behaviour
 

I've had an on-going problem with the CC that I've not been able to cure. I've taken all the electrical connectors apart/cleaned them and that did help, but it wasn't the cure. Problem with CC: The first time I engage CC it works like a Cadillac. I can disengage it while still in that first key ON day, but once I turn the car Off, during the nextkey ON cycle, it will not act like it did. It goes into herky-jerky mode where it gets up to speed, lets off, gets up to speed, lets off/etc. This is 'annoying'. It's useless trying to use it after that 'first of the day' key Off. No codes displayed. I believe it is heat-related, because it does not act this way in cold weather. If this behaviour description offers any clues to anyone familar with the CC, I'd sure appreciate some advice.Thank you for anyhelp solving this erratic behaviour!

RE: Cruise control behaviour
 

I would look for a soft vacuum hose to the servo or where the hose attaches to the source. Heat would make it even softer and possibly collapse restricting source vacuum

RE: Cruise control behaviour
 

Thank you Mr. Carnut! Great advice! Prolly a good idea to replace all the vacuum lines....11yrs for a life-span is sufficient. Well those under the dash can stay....no fun under there. Again, thanks. I'll do some line testing and get back with results. I appreciate your help.

RE: Cruise control behaviour
 

My 84 Eldo does the same thing about twice a week!!I dont drive far to work (8 miles in town) haven't replaced hoses yet. One other thing to do is apply dielectric grease to wire harness at servo.

RE: Cruise control behaviour
 

Yeah, I use the grease. Anytime I disconnect something electrical, the grease goes on. I drove around about 1hr this afternoon in the 100dg+ temps and checked the hoses when I got back. None of the vacuum hoses to/from the servo are soft, but I don't know about those that disappear into the conduit. No time to check them today/tomorrow, but Sat/Sun I'll sic my Mity-Vac pump on them and testfor integrity.If it is a heat-related problem, it must happen due to the heat build-up under the hood when the vehicle is parked. Maybe I'm getting a little closer to the cure.....Thanks

RE: Cruise control behaviour
 

Keep in mind I said collapsing. So the mighty vac might not verify a leak per se. So refreshing to converse with someone willing to do the proper diagnosis logically! There is one other hose at the brake pedal switch that dumps vacuum when brakes applied, so ck it as well. Good idea to use dielectric on the engagement switch connector underdash as well.