I know I'm going to sound completely stupid, but recently I discovered the right tail lamp or brake light does not work on passenger side of the 09 XF I own. In removing the tail lamp assembly I can identify the amber turn signal bulb and the back up bulb, but what's up with the tail light and brake light itself? Please don't tell me I have to buy a complete tail lamp assembly on this car to fix a burned out lamp.

 

Sorry but you need a whole new light fitting, the brake and tail lights are LEDs and are not "serviceable" (Jag speak).
Used ones come up on Fleabay etc from time to time, a helluva lot cheaper than new, but of course you take a big chance that whatever you get may be just as dodgy as your existing one or about to fail any day now.

 

I beleive there may be one or two shops doing repairs to these lights, although I have to say I have no personal knowledge. Lights constructed like yours are used by most manufacturers these days, and the main problem with replacing individual LEDs is splitting apart the front lens and rear moulding, but it can be done with the right tools. However, how do you know it is the LEDs that have failed ? What is more common is broken wires in the loom running to the light unit.

 

I'm with Fraser.

The stop and tail lights are an LED array. Its not uncommon for one of the individual LEDs to fail (but they do last a very long time). If none of the lights are working then either you've had a huge over-current that has cooked all the LEDs at once, or more likely they aren't getting any, or sufficient, power. The quickest way to check this is to disconnect the cluster and measure the supply voltage to the lamps and the resistance of the LED array. If you don't see a supply voltage then there's something else wrong in the car, if there's infinite or zero resistance in the LED array something is up with it.

 

Gotta be honest, this electrical stuff is lost on me. Might as well be looking a flux capacitor. As far as symptoms, I have now noticed upon further inspection, that the back up light as well as all led tail and stop lights are not working on the right side only. Turn signal and the led side marker array ARE working on that side. Everything on left had side of car is working. So I'm guessing I have a supply issue to the cluster that powers the led tail/brake and back up. But not sure how to trace that.