I've had multiple jeeps and fixed everything there is to fix but I have yet to have a cruise control issue until recently. I'm not familiar with the setup for XJ's but sometimes CC works, sometimes it does not. Every now and then, I'll be in CC and it will turn off and scare the **** out of me when I'm going down the interstate. The only reason I like to have it is because I live in Texas and drive down the interstate almost everywhere I go and when the CC isn't working, I tend to speed.

Is that a vacuum-type issue that I could easily fix possibly?

Also, glad to find a forum for Jeep Owners. Not many people understand the jeep love mentality I have, so it's nice to find others!!!

 

The sometimes working and sometimes not is a vacuum issue.

The turning off is likely because there is a brake pedal switch under the dash which has a plunger that gets worn and sticks. The sensor tells when your brakes are pressed. Last one I replaced was fairly cheap IIRC.

Oh and Welcome!

 

I would check the vacuum lines and the vacuum ball if you didn't already. From what I've read, the cruise control module itself is the most likely culprit if the settings buttons and lights work. Also, the VSS could be suspect as it sends a signal to the cruise control module. Another thing to check would be your brake switch. It could be out of adjustment and be disengaging the cruise at random times. Hope this gives you some ideas.

 

The light is on when it is working and turns off when the CC turns off. So it recognizes that it is on and off. Not sure if that makes any difference.

 

The VSS sends a signal to the CC module? Is this the case on later model XJ's?

My '91 has a simple vacuum servo with 2 hoses going to it and one wire IIRC.