Help, stood the car for 3 weeks over xmas and now the brake pedal doesn't illuminate the brake lights or allow the box to be released from park. When you move the lever you can hear a click behind the dash, but there is no click at the stick when you depress the pedal. Strange thing is that the cruise cuts off when the brake is pressed, so the car knows the pedal is pressed. I've got the car moving by manually releasing the box, but I'm aware that someone might hit me as there's no brake lights. As far as I can see my car only has 1 sensor at the pedal, if there's another I need my eyes testing. Any help appreciated.

 

Hi John,

Welcome to the Jaguar Forums!

We'll be happy to try to help, but in order to provide accurate suggestions we really need to know the year, model and engine displacement of your Jaguar. Please let us know and we'll go from there!

Cheers,

Don

 

Thanks, it's a 1994 4.0 soverign xj40

 

Hi John,

Thanks for your car info. You can download the 1993-94 XJ40 Electrical Guide here:

http://www.jagrepair.com/images/Auto...ec%20Guide.pdf


See page 73 of the pdf file which shows the schematic for the cruise control system. There are separate switches for the cruise control inhibit and the brake lights, but they are combined in the same case, which is mounted at the top of the pedal assembly. The brake light/cruise control inhibit switch is Part 12 in the diagram below:


It could be that the brake light switch has failed but the cruise inhibit switch is still working. Another possibility is a problem in the wiring circuit for the brake light switch. The Electrical Guide will give you ideas of where to look.

Please keep us informed.

Cheers,

Don

 

Thanks for the electrical manual. A squirt of wd40 into the assembly worked after a few hours. Going to look and replace it tho

 

Both my micro switches have failed with the car standing over the winter. The micro switches are available easily from Ebay and the like but I don't know whether they should be normally open or normally closed when the pedal is not pressed. The replacements can be wired either way. Also if one is normally open and one normally closed which colour coded wires go to the switches as the link above doesn't seem to work.
Thanks
The micro switch is the same one used for the X300/305 boot release button also.

 

I just checked and the link(s) above do work, (you need a .pdf reader to read the manual though), plus it takes a little time to download so just wait till it loads completely then save the document.

Larry

 

Hi Atco,

Just for clarity, on which of your many Jaguars have the micro-switches failed?

Cheers,

Don

 

Don
It is the XJ81 and definitely both failed as I have checked them with a meter.
I have sold the other V12, must update my signature.
Thanks
Charles

 

I found the wiring diagram, Thanks guys
It wouldn't download on my PC but it did immediately on my iPad!
Brake switch N/O wires: white/orange & purple/blue
Cruise inhibit N/C wires: White/blue & purple