Had a 'battery drain - left brake light always on' fault. Eventually figured out it was X300 Security & Locking Module. There are a number of possible symptoms when these fail. Mailed it to "Module Repair Pro" in Van Nuys, California. Please look up www.ModuleRepairPro.com . Check out their on-line listing. I'm happy with their work. One year warranty, they apply their own seal, peaking inside may void warranty. So cannot testify to their work quality. Functionality fine. According to their brochure and on-line site, they fix all kinds of every-bodies module, speedometers, radios, ABS & HVAC modules. And a buncha other stuff. Prices good. Hardest part was finding the manufacturers assembly sticker showing all the Jag's module suffixes. (VCAT) While a module may show a rather lengthy number, usually the actual programming version is not listed on the module. Mine (an XJ308) was on inner bulkhead under trunk DVD player. Under the lining. But could've been one of about 6 places.

Am thinking these guys could be the answer to many folks problems, especially as our Hoopties age.