no cruise control

[mjtr21]

i was driving along the highway the other day and i went to use the cruise control and it didnt work. i believe it is vacuum operated but not sure. also my 4WD does not engage the front wheels either. could those two be related in some way? thanks.

[DelCoch]

What make, year and engine code is your vehicle?

[mjtr21]

oh sorry its a 1997 GMC Jimmy with the 4.3 engine.

[mike2004tct]

Sounds like a vacuum problem.
Check the small hoses from the vacuum ball to the manifold and to the transfer case.

[mjtr21]

okay thanks. so if i replace one thats leaking it could help fix my 4WD problem? i will check when my brother brings my truck back here.

[mike2004tct]

Quite possible.
Because both the cruise and 4WD work off vacuum assist, I'd guess a cracked or disconnected hose from the manifold to the vacuum ball.

[mjtr21]

okay i will check today. yesterday was snowing really bad and i couldnt get out to check it. i also notice when i am slowing down to a stop the rpm's fluctuate, so i guess this is related to my vacuum problem. thanks.

[Snilloc]

i think my blazer may be having the same vacum loss problem. my cruise stopped working over a year ago, and recently my 4x4 stopped engaging. Checked the vacum actuator and had no vacum going into the solenoid. So i'm guessing i have a leak going from the manifold to the vacum ball. I'm not the most mechanically inclined, but is this something I could find/fix on my own? Any help would be apreciated.

[old_master]

Cruise control does not use vacuum, it is all electronic. Check connectors, fuses and control cable where it connects to the throttle linkage.

[mjtr21]

yeah haha i kinda realized that when i didnt see any vacuum hoses coming out from the servo motor. thanks i will check fuses and the connector.