I've been very fortunate with my '98 xk8. I invested $800 at a local high quality repair shop to give it a good "going over". They found several things, and corrected them before they became a problem for me. A couple of minor problems, windows going down on their own, and such I was able to resolve with the fantastic help of this forum. At my age I realize that I am way out of my league compaired to most members here at this forum (Where have all the Edsels gone"? But I'm not too proud to ask a question. The cruise control does not work. Before I start blindly trying things, ( have discovered that I know even less about Jags than I do about women) perhaps I can get a logical list of things to check first. Thanks, in advance, to anyone who can help.

 

Is the vacuum hose connected to throttle body? While this would kill cc, you'd get restricted performance too. Ah, darn - just remembered cc resets in this case with ignition key cycle, then fails when cc on and you go uphill.

Next idea: faulty brake switch (unfortunately more likely without restricted performance and cc reset with each ignition cycle)

Please say is button lite on?
John

 

I replace my brake incandescent brake bulbs with LED and at this time my cruise control and adaptive cruise stop working. After replacing back those bulbs, the CC came back to life.

 

TO JOHNKEN and Ledmi, I apologize for taking so long to respond, but sometimes family matters supercede my needs. As to my cruise control not working, when I start the car the cruise control on/off master switch comes on and stays on, as does the sport mode next to it. When I start driving and reaching speed about 55 mph I press the + set switch, cruise control does not engage, the light in the on/off master switch goes out (sport light is also out) and pressing the master switch will not bring the light back on. I have not changed any bulbs or tampered with the electrical system. Any ideas?

 

The switch beside the sport mode is the limiter speed.

i recommand that you take the owners manual and read the cruise control section and the limiter speed section too

 

on my ‘02 XKR , and confirmed by the owners manual section 3-19, the cruise control master switch is indeed indicated to be next to Sport Mode switch. Don’t know about the OP’s ‘98 model.

Z

 

I have indeed read my "Divers Handbook" on cruise control and page 29 clearly shows the "on/off master switch" located in the gear selector surround and next to the "sport mode" switch. I have also checked the throttle bod vacuum hose, and all seems ok there.

 

Oc, open the hood. Look at the throttle body, see the vacuum hose? Is it still connected?

I'll try to find a photo. I went through the same stuff back when my engine mounts wore out. The movement of the engine did 2 things:

Pulled the hose off

Disconnected the "silencer" appendage to the air filter box.

John

 

See post #5
https://www.jaguarforums.com/forum/x...Cruise+control

John