My 2003 Jaguar XJ8 has only the lamp on the driver-side rear door illuminated (the "puddle lamps" on the lower-rear corner of each door). The lamps in the other 3 doors are all good (they light when removed and powered with a battery, continuity across the filament, etc) but do not illuminate when in the door.

Any guesses as to why, or where I should start the diagnostic process?

 

Ah ha! I searched the forum before posting and failed to find the post below, but then picked it up in a Google Search for "X308 Puddle Light Switch". This seems to be one of those common issues that everyone gets sooner or later. And so, I'm off to the local Pick and Pull for three working microswitches. If anybody has these kicking around and wants to sell then to me, please let me know.

See: https://www.jaguarforums.com/forum/x...de-door-43223/ for the sad tale of these dodgy switches.

"Robert DIY" on YouTube has a great video that shows at about 9:50 how to pull the guilty microswitch out of a door latch assembly, and the same method can be used to acquire a replacement. See: . This same video shows how to remove the door panel (easy) and replace a faulty door lock actuator, also prone to break. In fact, the probable reason that the rear door on the driver-side is the only door with a working puddle light is that I just replaced the entire lock and actuator (and consequently the microswitch) with a NOS unit to deal with a non-working actuator. All the other microswitches are original. Damn, this car is earning its reputation for electrical glitches!



Pry up to release the microswitch and then slide it out from under the tab above.

 

I was going to guess microswitches as my driver's door is slow to light the puddle lamp when it's below zero.