How to Fix Inoperative Cruise Control on Series III XJ6 Jaguars

Jaguar Parts Technical Information

The cruise control system in these cars has a few common problem areas which will render the system inoperative. Fortunately, they are easy and inexpensive to repair. If your cruise control doesn't work, check the following:

Forest Gibson, one of our list members, added:

"Your listing of items that could cause the cruise control to fail was good but it missed one point that I experienced in my '88 XJS. The lower end of the shift selector operates a pair of cams which in turn control a pair of micro switches mounted just below the console. One switch keeps the starter from operating if the selector is not in NEUTRAL or PARK. The other switch cuts off the cruise control if the selector is not in the DRIVE position."

Jose Maymon, another list member, added:

"Regarding your checklist for Cruise Control not working in series 3 XJ-6: I've had to go through the same trial & error list you provide in this weeks's Techbits, HOWEVER: You missed the most important check: The combination Reverse Lamp / Start Inhibitor / Cruise Control Activator Switch which is mounted in front of the gearshift (under the Ski Slope cover), and which is activated in conjunction with the ON-OFF Switch mounted behind the Gearshift Lever; If this combination switch is not properly adjusted in relation to the gearshift-position "D", the Cruise will NOT come ON. In fact, this switch is reverse-wired, so that "off" is really "ON" for the purpose of the Cruise Control."

Jose Maymon added another update: 06/20/2004:

"Regarding the posting I made years ago to your Series 3 XJ-6 Technical Tip maybe the following correction should be added: It appears that the microswitch in question has nothing to do with the Reverse Lights in my 1984 XJ-6 as I stated in that posting; I am referring to the Start Inhibitor/Cruise Control micro-switch located in front of the Gear Lever Quadrant, under the center console 'Ski Slope panel' (where the ashtrays mount to)."

"Yesterday I was adjusting my Gear Selector Cable, in order to locate the 'sweet spot' adjustment for the Reverse Lights to come on, because they were not coming on when the Gear Selector was moved to 'R' unless I pushed the Selector slighty forward. I removed the Start Inhibitor / Cruise Control micro-switch from its mounting and disconnected it from its Harness, in order to bench test it outside the car, but I continued to adjust the Cable when all of a sudden the Reverse Lights came on. (I placed a mirror in a stand behind the car to be able to see the lights go on and off from the driver's seat and through the rear view mirror). Puzzled, I continued to fiddle with the cable and gear selector and the Reverse Lights kept coming on and off, so obviously they are not dependent on that micro-switch, obviously they are activated by the transmission mounted, cable-activated Reverse Light Switch."

"My apology for any confusion I may have caused anyone, but I should add that there seems to be confusion among technicians and do-it-yourself enthusiasts about the functions of that micro-switch. Furthermore, some XJ's have a 3-wire microswitch and harness, and some have a 2-wire microswitch and harness. It is possible that in later cars, the 3-wire microswitch and wire harness DOES control the Reverse Lights adjustment, but in my 1984 XJ-6, the 2-wire microswitch/harness does not. "

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