Stuck brake lights- always on
 

First off- hey, all! Apologies for being inactive for over a year but all is well with 'Kate'. I've been too preoccupied with my rural property and sorting a Land Cruiser overland build lately. I sold my S8 about a year ago to get into all that.

Anyhoo, the Jag is largely stationary and getting driven every couple weeks to keep things moving and such, but is now more of the weekend pleasure cruiser, with rare trips to work during the week. It's great at taking the scenic road through the countryside to fetch pizzas. Currently no CELs! I noticed in the past month for some reason that the brake lights are now stuck on whenever the car is on. This may have been covered in another thread, but I couldn't find what the cause might be. Past links welcome. Is it a switch somewhere? It's both taillamps and the 3rd brakelight together. TIA!

This is a very like wiring guide I made up to the X308 and will get the specific wiring guide to the X100 in the morning . Notice the difference between the brake light ( in purple ) and the running light ( in blue ) .

Likely the brake switch. There are lots of posts on this. It sits in front of the brake pedal arm. Somewhat of a pain to put back in place. It is made of 2 micro-switches that are known to go bad. Even the replacement part eventually goes bad, and is not terribly cheap either. You might want to (gently) press the brake pedal a few times to see if it makes itself work again for a bit.

If you want it fixed, get a new assembly, and then repair the old one (solder in new switches). The switches have been identified, and are super cheap online. Obviously, it requires some (basic) soldering skills. The idea is that the next time around, you already have a replacement switch ready to go, hopefully made with better quality parts.

+1 Fmertz is correct the problem is most likely that switch. You can get a look at it with a mirror. There should be a plunger sticking out that is touching the pedal arm. They can get stuck in the depressed position. try freeing it up. If it is extended then it is time for a new switch.

This is what you are looking for (item 14):

Attachment 210789

A real pain to change.

Graham

http://www.jagrepair.com/images/Auto.../jagxk2000.pdf.....see page 109

Very much the same between the X100 and X308 with the exception of wire colors . If you want to test the switch just bypass it by removing the black or green / black wire before the brake switch ground .

Note the adaptive dampening circuit can also give it a ground......see page 102

There is a error in the X100 wiring diagram on page 102 as the adaptive circuit should not have the mechanical brake switch in it . The brake switch is the primary device to signal braking and the adaptive is a add on .

Thank you, all! Been out of town and didn't get the reply notifications. Would it be OK to spray with electrical contact cleaner if it's sticking?

Will investigate further this weekend.

I tried spraying mine with contact cleaner, it made the problem intermittent.

I bought the part, built a little deck to lay on and tried to change it myself but at 6' and 225 lbs I'm too frikin big to get in there without taking out the seat. So I paid a tiny, girly handed fella $100 to put it in. Money well spent and no further light, cruise, or lights on the dash problems.

Replacing the brake switch can be difficult but it can be done two ways, removing the bracket or just replace the switch housing. The attached link should help.

Link JagRepair.com - Jaguar Repair Information Resource

Outstanding! Thanks again, Gus.