Cruise Control Doesnt Work

The next issue I have is my cruise control does not work. I would like for it to work, but if it doesnt then its no big deal.

What is the most common cause for failure for this?
Mine is a 88 XJ, auto 4.0L with the full time and part time tc.

Did it work recently and then just stop working recently? New vehicle to you and no history?

A vacuum problem can cause a problem with cruise control. Check all hoses and vacuum sources associated with cruise hardware for leaks.

Check for a fuse circuit and be sure the fuse is good.

There is a white switch, high up on the brake pedal. Yours should have wires for the cruise control and the auto that tell those computers when you've hit the brake. It also has a vacuum line attached to it that breaks the vacuum on the cruise solenoid as a failsafe.

This switch can get gunked up and stop working, causing both the cruise to stop working and the torque converter to stop locking up. You can check it with a meter. It should have continuity with the brakes off. The good news is that the switch can be cleaned. There is a screw on the side of the bracket that holds it. Remove that slow the bracket to the left and it'll come off. That's easier then trying to get the switch out. He switch itself has some small tabs that you can press to pop it apart and clean and regrease.

Check vacuum and electrical connectors at the doohickey under the hood before doing anything else. If those are all good you will need to test the cruise control module, which for RENIX vehicles is a separate component under the dash (a yellow box I think). There are ways to test the various input signals from the stalk and brake, and the output from the controller as well. You really need an FSM to do all of this.

1988 Cherokoo said:

Should be a pretty simple fix.

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ROFL @ optimism

don't post links to FSMs read the sticky