I have a 1998 XJ8 which I cannot drive now as the brake lights are not working, and I need to get a warrant of fitness. Occasionally in the past I have had to press the brake pedal several times in order to get the gear lever out of park. That seems to imply a faulty brake switch. It looks like a standard Cherry micro switch. When closed, it has a resistance of 500 ohms. That surely is not normal, as most micro switches have a resistance of less than 1 ohm. But if I short out the switch, the lights still don't work and the gear lever is still stuck in park. Are there any experts who know what is happening? Surely a new switch would be no better than a dead short.

 

You might wish tp check for a failing SLCM or security locking control module. (in the trunk under the fuse box) If the rear brake lights do not light,
but the 3rd brake light operates as intended, then that would be my first thought. In the forums, some members have just replaced the module..
If I remember right, these modules are specific to the model year of your Jaguar., There is a code specified in the CATS list that is usually found
on the shoulder panel of spare wheel well. The part number to look for is the number after "SLCM" ----, which shows the part number and then
the program code. The replacement must be a match for it to work.

 

The problem was the switch, and I shall install a new one tomorrow for under $5.
When I originally shorted out the switch I must not have had the ignition on. I was under the wrong impression that the brake lights were supposed to work without the ignition on.
It's very cramped under there, and impossible to see the brake lights.

 

Hmmm... that was anti-climatic.