hello all, i recently purchased a 99 glt with 125,000 miles. the cruise control does nothing when i attempt to engage it, and while in park, the rpms go from 850 to 900 back down to 850 and the pattern continues. i have heard that it could be a vacuum leak causing the idle surge, and that a vacuum leak could cause the cruise control to be inoperable. can anyone confirm this and explain what i could do to test it? the car also seems to have pinched wires in the rear for the rear wiper. it only works if the tailgate is at least 30 % open. any help would be greatly appreciated
thank you

 

FIrst I would locate the throttle body. Just follow your air intake pipe and see where that meets your throttle cable. Remove the large plastic pipe and clean the throttle plate real well with throttle body cleaner. Also look at the sticky on this forum about common issues. There is an article about cleaning the IACV. Though I have not found mine yet since the pictures are from older models. I know it is hiding n there somewhere...

I am not sure about Volvo, but on my 200sx, the cruise control cable is controlled by a vacuum pump. That cable should be right next to the main throttle cable. Follow it back to either a vacuum pump (indicated by hoses going to and from the intake manifold) or it may be electronic. Check to see if everything there is connected well.

Heck, you may get lucky and find a disconnected vacuum line at the cruise control pump and that would cause both problems.

Oh yah! One more thing. Don't forget to post back to tell us the progress and how it was fixed.

 

Chrisace, thank you for your reply. can you explain to me what sticky means and where to find it? I see a few sticky posts when i open the forum, is that all of them because i cant find one on common issues. Thanks

 

Stickies are posted at the top of each section. Above the new posts, right at the top.

I wish you luck that the vacuum line fixes the problem. My cruise control wouldn't engage in my 02 70, turns out it was an ABS sensor at one wheel. I spoke with Volvo about it, they told me there no less than 7 inputs that if not happy will prevent the cruise control from working. In mine, the cruise control thought the car was braking. And no lights, messages or anything else showed up. Only the cruise wouldn't work.

 

That brake sensor makes since. Cruise controls are programmed to turn off when the brake is applied. Good luck!