I've been having issues with my cruise since I bought the car. It works fine maybe every tenth time I drive the car. The other nine- nothing. My brake lights work just fine, and I believe the vacuum pump is alo functioning, though I'm not 100% positive. I believe if the pump was bad, it would never work. Anyone have any ideas?

Edit: The master on/off switch is always on, as well. Thanks!

 

What year???
Usually the vaccum line crack which causes the system to not work.

 

It's a 1998 DI. If the lines were cracked and/or leaking, would it still work every once in a while? When it does work, it generally works fine until I shut the car off.

 

Hi Core_Shot.
Have a look at the switch on your brake pedal.They tend to give a lot of problems.Open the fusebox cover under your steering and look at the pedal bracket.There will be two switches on there.The one in question is the one with a vacuum pipe on it.Check that the pedal push the plunger all the way in.If it does,remove it and suck on the little pipe.With the plunger all the way in ,you should not be able to suck air through it.When you release the plunger you have to suck straight through.
Regards
Marius.

 

Yes if there is a small leak in a vacum line it can still work once in awhile. Depending on the outside temp the hose can expand just enough to close the leak, or it could be in such a place that is wiggles enough to open and close the leak when you drive.