All know that an intermittent problem is hard to solve: When message Engine fail safe mode/check rear lights comes on, cruise control is inop. and CC light on console goes out. Stopping, cutting ignition ogg for few minutes restores cruise control, but then maybe 30 minutes it happens again. Jaguar ship tells me that the rear lights & cruise are somehow connected. I was told to check all rear lights for same brightness, which I did & all are the same. How do you trouble shoot & correct this issue?

A.E. Breard

 

Hi A.E.,

The connection between the rear lamps and the Cruise Control is the brake light switch next to the brake pedal lever. The switch has two circuits, one that operates the brake lamps, and another that cancels Cruise Control when the brake pedal is depressed. You might try disconnecting the brake switch, cleaning the switch & harness connector contacts with electronic contact cleaner spray, allowing to dry (or dry with compressed air), and reconnect. If that doesn't help, you can test both sides of the brake switch with an ohmmeter.

Cheers,

Don

 

Don, thanks for the tip! It seems to me that there are several circuits which suffer from corrosion & the like. Can you identify for me which is which? The Jaguar shop that I use told me this: "Get someone in the car, turn on all the lights, and see which of the lights is brighter or darker than the rest" That advice was worthless. They are all bright. So today I changed one bulb that was slightly dark. I'll see tomorrow if there is any difference. Meanwhile, the hazard
flashers started flashing, and would not turn off, and I still can't find the fuse that controls them. I found on this forum a solution" stick a credit card in the gap around the flasher switch & jiggle it until the flasher stops. Well, by George, that worked! spoliation: prdize switch out & clean the contacts with contact cleaner, then put it back together. Several people had the same problem, which was caused by grunge building up on switch! Mine is a 2002 model XK8, wich I bought last May, and it is a great driver!

 

The circuit for the Cruise Control cancellation is the White wire with Blue tracer line and the Blue wire that connect to the brake switch.

The circuit for the brake lamps is the B lack and Green/Black wire (those two wires come to a connector and become White/Blue and Orange/Green respectively).

You can download the wiring schematics for your car at this link, thanks to our member Gus who hosts jagrepair.com and our member motorcarman (Bob) who supplied the original files for upload:

Jaguar X100 Electrical Guide 2002

Cheers,

Don

 

Do you change your regular bulbs for LED. It happen to me and the car went on safe mode. Put back regular bulbs and back to normal

 

Don, I uncoupled the only connection I could find, although it was not attached to the brake pedal arm. Is this the right one? I can't see any outher couplings.... Armand

 

Hi Armand,

The brake switch is Part 14 in the diagram below, and you can see its electrical connector dangling below the switch housing. The switch housing has two threaded studs on the top end that mount through holes in the firewall/bulkhead/pedal box.

Just to warn you should you determine that your switch is faulty, replacing this switch is a fiddly job. Removing the old switch is not too bad. First, note how the switch is installed in relation to the brake pedal lever. Then remove the nuts up top of the pedal box (in the engine bay) and use an extending magnetic retriever to help prevent the nuts falling as they come loose.

To install the new switch, I tie a length of strong thread or fishing line around the top-most stud on the new switch and feed it up through its respective hole. Then pull the string to draw the new switch into position and get its studs through the holes. Loosely install a nut on the stud without the thread, then cut the thread off of the other stud and install its nut. Now you can snug up both nuts.




Cheers,

Don

 

Wow, Don, you know your stuff! This obviously, is not the connection that I sprayed contact cleaner on. Appears I could do this without too much anxiety. Do you have the part # of the switch and a source other than the dealer?
Also, before I do this, what exactly should I look for to determine if this is really the part I need?

Thanks, Armand

 

Don, could you possibly take a pic of the mechanism in the engine bay & send it to me? I don't see anything resembling the exploded diagram....

Armand

 

Hi Armand,

The brake switch is in the driver's footwell. You access the connector from near the brake pedal lever.

All you will see in the engine bay on top of the pedal box is the two small nuts that hold the switch bracket in place.

Here's a photo of the switch. I just grabbed it from eBay, a good place to find photos of Jaguar parts:




Cheers,

Don