Hi folks- the cruise control on my 1999 xj stopped working all of a sudden. Is there a fuse somewhere? I couldn't find one in my owner's manual. Any suggestions on what to look for? Thanks.
Richard

 

The cruise control all of a sudden stopped working on my 97XJ a couple of weeks ago. I found a vacuum line broken,,,the hard plastic one that goes from one side of the servo to the other,,,pulled out the broken bit and plugged the line back in. It now works better than it ever did.

 

Does the cruise light on the dash illuminate like normal?

Vacuum is typically the issue with the XJ's cruise control you'll also usually get defrost only on HVAC controls no matter what setting you have or if it's a smaller leak you'll get a "wandering" or slow responding level setting.

on my 95 I discovered the 15 amp "ign" minifuse in the PDC is what my cruise circuit is on but the 97+ use a different PDC setup and I'm not sure what circuit it will be on. I do know I've never seen "cruise" on any fuse break down

itll probably take some studying if the wiring diagram

 

Okay, power to the speed control solenoid on the vacuum actuator comes thru the brake switch and the PCM controls the grounding of the circuit. The solenoid controls the vehicle speed by either applying vacuum or venting it. The vacuum supply circuit consists of a plastic pipe from the intake manifold to the vacuum accumulator under the battery tray or in front of it, with 2 "T" fittings in the line. One supplies the heater and the other supplies the cruise control diaphragm and solenoid. There is a one way check valve in the pipe just after the manifold connection designed to close the heater doors to outside air after the engine shuts down with vacuum stored in the accumulator.<br /><br />SO.... it appears the brake system fuse controls power to the cruise system. It looks like that's fuse 21 in the PDC. This information is right out of the FSM for my 2000 Cherokee Sport.<br /><br />BTW people, that hard plastic pipe is only there to replace the rubber hose that used to be in all vacuum systems, but has been replaced because hard plastic resists heat and vibration better than soft rubber. You can use rubber hose for any repair but you'll have to watch it for deterioration after awhile.