Cruise Control

[4runnertank]

So my cruise control hasn't worked since I bought the truck 2 years ago, and I was wondering why. It's a 1989 4runner SR5 with the 3.slo. It has the cruise control button to the right of the steering wheel, which turns green when I press it, but does nothing anybody have any ideas how it works or what may be wrong. This is something I am absolutely clueless about!

 

[the_dingman]

The button by the wheel just turns it on. Once to speed, you have to set it by twisting the control on the wiper multi-switch.

If it still is not working, the vacuum unit is probably out. I had to replace mine to make it work.

 

[DC runner]

You have to understand how the system works before you can figure out what is wrong. It is 1 part computer control and 1 part physical vacuum.

The light being on tells you that the computer/electrical side is probably fine. The soft spot is the vacuum. Everyone moved away from vacuum due to them being prone to breakdown and leaking.

Simply put...you have a vacuum motor and lines that connect to the throttle cable. When you turn cruise control on, it will sense where the speedo is and will engage/disengage vacuum on the throttle to control your speed.

Those lines are never replaced and if you still have the original.. I would suspect either a serious leak or the pump is out.