Hi from a new XJ8 owner.

I have had a 2000 XJ8 sovereign (UK) for just over a week, last night the main brake lights came on and stayed on, even when ignition is off and key removed, removed the bulbs to avoid draining the battery.
The high level (rear window) brake light still works perfectly which I suspect rules out the brake switch.
Any ideas?
Could it be a fault with the Security Locking Module and if so how awkward is it to replace?

 

The stop lights do indeed take an output from the security module.

Although the brake switch operates both sets of lights, the high level is supplied via relay 5 in the trunk fuse box.

Before you get into thinking about spending, try disconnecting the module, cleaning the connectors and then refitting, making sure they are fully seated and try again.

Hope this helps,

 

Thanks Jim I'll give it a go.

 

Tried disconnecting and cleaning the module connections but no luck I'm afraid.
Now have a replacement Security Locking Module but need to know if I have to reprogram the keys and if so, how?
Any assistance very gratefully received.

 

Check the number on the new one is the same as the one fitted. If so, you should be able to plug and play.

I would try plugging it in first anyway.

If the module is programmable it will have an EPROM in it. Remove the old EPROM and fit it into the new module and that should save you a trip to a dealer.

If none of the above works then you may be off to the dealer anyway.

 

Any good Indie Jag specialist should have the correct diagnostic software (IDS/WDS)to reprogram any module -try Eurojag/black country Jaguar etc for one, and have the local indie reflash the module.

As suggested, a year related module should be plug and play as long as the VCATS module number is the same, the VCATS list is located in the step around the spare wheel well, carpet will need to be bent to read it. The important bit is the 3 digit code at the end, your car's program, eg LNG****-008.

The only time you need to reprogram keys is when you get a new one, again IDS is required.

I like the idea of swapping the epromm, but not everyone has the skill or patience. There's another member that id'd the failed component and fits a new part on here too.