Originally Posted by christine_208

Perhaps a fresh start is appropriate.

What symptoms are you experiencing?
Are all your systems working fine except for the cruise control? In what way is your cruise control not working?
Failure point in the cruise control system can be the physical connection to the throttle (breaking), the cruise control module in the engine compartment, or a malfunction of multi-function switch on your steering column.


Is your HVAC system working appropriately? In these Blazers where the air flow is directed controlled by vacuum actuators. A very common problem is that the hoses under the hood that supply the vacuum can rot and leak. (See a link in my signature file) The vacuum storage container seldom is the issue.

Finally, our cruise control systems are all electronic with no vacuum interface. You have either misunderstood your mechanic, they did not explain it well, or they don't know what they are talking about.

And as for dealers, 10 years ago I dropped my then 11 y.o. Blazer at the local dealer to fix my parking break. When I got it back, it worked worse. For vehicles out of warranty, they do not always know what they are doing.

Long story short, they did not even know how to properly adjust the brake shoes even with the access to the official service manuals. I then had to spend an afternoon working out how they worked on my own the following weekend. Later when I got a copy of the official service manuals I found that I was correct.

Originally Posted by Tom A

There are a number of things that will keep the cruise control from working, like a bad brake light switch, faulty vehicle speed sensor, etc. The best way to test those things is with a scanner that shows live data.

Originally Posted by SuperComp2766

The shop that had it did use a scanner and it showed the cruise to be working, so I assume the dealer is telling me right when they say it's getting a signal to work, but it can't because of the vacuum problem.

Originally Posted by christine_208

Perhaps the problem is that the engine is not working properly because of a vacuum leak and that is what is making it hard for the cruise control to function properly?

Just to be sure I checked my 1999 GM Service Manual and there is no connection between the cruise control system and the vacuum system. I also looked to see if the a code reader is ever used to check the cruise control system and it is not. If you like I could scan the pages from my manual for you to see and perhaps pass on to your mechanic. (It's 19 pages)

You can easily check the HVAC/4wd vacuum supply hoses yourself. They should not be brittle, crumbly nor loose on the nipples of the fittings. If they are, they are likely leaking. The hoses tend to fail after these trucks get to about 15 y.o. Fortunately, if they are bad, fixing them is easy and cheap.

There are a few other hoses that tend not to leak but could cause problems if they are. If the HVAC/4wd vacuum supply hoses are ok, the next culprit would be the one that goes to the PCV fitting. I had to replace that one.