Just discovered that my XK8 brake lights intermittently stay on after releasing the brake pedal. A few short taps on the brake pedal and the lights extinguish, I'm thinking it is a sticking pivot point or sticking micro-switch inside the unit, no codes just the light issue. Anyone experienced this? Plan on pulling it out next week.

 

The switch has a plastic 'ratchet' mechanism that can be pulled out and when the pedal returns, it will set the switch to the correct position. Don't pull the brake pedal OUT after resetting the ratchet. Just let the pedal return to the rest position.

bob

 

Thanks' Bob, I will give that a try.

 

Well, pulled the switch out, ratcheted the plunger out, plugged it in, turned on the ignition and brake lights came on. Unplugged the switch and the brake lights go out. Measured contacts 1&4, according to Exterior Lighting: Rear, Fig. 09.2 this should be an open circuit, dead short, push plunger, circuit opens. Put meter across Pins 2&3, open. According to Adaptive Speed Control, Fig. 06.4 this should be normally made. Plugged the switch back in, turned on the key, instant brake lights, press the plunger, lights go out. Don't understand how both switches are working the exact opposite but. appears they are. Can anyone confirm the pin readings?

 

At rest (no pressure on the pedal), the arm attached to the brake pedal should contact the plunger part of the switch and push it in (at least some), same as pushing it in with your finger. When the driver pushes on the pedal, the bar should release the plunger, the way the switch would sit on a bench (plunger out).

In your case, it seems like this adjustment is out, i.e. the arm on the pedal does not push on the plunger enough. This is where the ratchet built-in the plunger can help.

Best of luck, keep us posted.

 

See page 83 :

http://jagrepair.com/images/AutoRepa.../jagxk2002.pdf

Gotta run errands , any questions , just ask

Might have a floating relay contact or intermittent pulling coil , swap out

The brake switch gets a ground through the ignition switch at the 6 stop sign point on the print which is on page 45 . Move the key around and see if the ground disappears .

 

Motorcarman (Bob) & fmertz, had the correct solution, I made it a lot more work than it needed to be. Not knowing the brake switch was engaged when the pedal was in it's resting position I approached everything backwards. Switch has been reinstalled (what a pain) plunger ratchet adjusted and all seems to be working correctly. Thanks' to all for your help.