Cruise control slightly works

[sothrowd08]

I have a 1998 safari. The thing runs nice and hums quietly for a 300,000 mile vehicle. Only problem I see so far is the cruise control slightly works. I searched here for some answers and couldn't find anything that could help me. Everything I found either had no location advise, too much technical info with abreviations I don't understand, or it was for a van that is a 1995 and previous years.

So the problem I get is when I at a good speed I want to stay at, I would hit the button, let go of the gas, and it will catch for just a second and then it would slow down as if it lost it. I never touched the brake so that can't be it. It happens all the time, some times its longer than other times, but it will loose the cruise control eventually. It only lasts for a few seconds and not any longer. The fuse is good also.

I would greatly appreciate if any one can help me out with this problem

[Matrixx]

Hi sothrowd08

Welcome to the Forum

Is the SES light on?
Is this AWD or 2WD?
Do you have any after market items installed (IE: alarm system,remote start etc.)?
Thanks

[remark123]

Don't know if the cruise still works on vacuum, but if it does in the '98, check the accumulator ball on the pass side of the engine, or the vacuum lines. My '91 had the infamous vacuum line break, and that caused the cruise to quit working along with the HVAC control issues as well...

[astro355]

Don't know if the cruise still works on vacuum, but if it does in the '98, check the accumulator ball on the pass side of the engine, or the vacuum lines. My '91 had the infamous vacuum line break, and that caused the cruise to quit working along with the HVAC control issues as well...

Yes, check the vacuum line and the cruise control servo. The servo has a rubber boot built into it and if that boot is torn or cracked, the cruise will not work.

['cudapaul]

No vacuum, no hoses, no nothing in the 95 and up cruise control system.
There is a control module on the firewall that the cruise cable goes to from the throttle body. It is all electronic.
It uses an motor type of mechanism to wind a cable up to pull the throttle open, or unwinds to close.

I have had a similar problem and it wound up being the switch in the turn signal arm. If I pulled on the resume, and let go it would shut off. Also, the set button was intermittent, sometime it would set speed and other times it took several tries to get it to hold speed. Replacing the arm took care of the problems.

My guess is that when the contacts or plastic internal parts get worn it doesn't work reliably. You could try replacing it with a used one to see if that fixes it. If you do try to remove the electronic motor module on the firewall, be carefull. There is a certain way to disconnect and re-connect the cable. It's covered in the factory manual pretty well.

[sothrowd08]

thanks for all the useful info. I think it may be part of that rubber boot. My AC and Heat only blows through the defrost and not any other vents. I was playing with it yesterday and I would slide the button to the right and hold it. Eventually it would catch. If I held it there it would stay longer but increase the speed. If I hold the button in it will do the same thing, but will hold on for less time.

Would a turn signal arm from a 95 astro work? I know the cruise control on that one works, but I am getting ready to sell it so I don't care.

[Matrixx]

Hi sothrowd08

I would get one from the same year if you can. Funny thing about GM, is all the small changes they make to parts you don't see with the naked eye. If your going to get a used one at an auto wreckers then I'm sure they can tell you what years will and won't fit, but I doubt the 95 will, their was a lot of changes made between 95 and 98 that's for sure. Please keep us updated, thanks.