i dont know about MOT in the UK, but it doesnt present a problem in the US.

My passenger side (your driver's) has been doing that since about a month after i got my 2012. I tried removing it and heating it up or training it in some way, but the lens itself is sealed away from the connecter, so there is really nowhere for the water to go, plus since it is an LED, it never gets hot enough. I even tried putting the light in front of my fireplace, and it would help until it went back on the car. Even the Jag dealer said, and confirmed in the legal documents, that is not covered by my CPO warranty.

My next attempt is the rice-cell-phone method. I got a 50 lbs bag of rice to dump in a container and see if that helps. Keep you posted.

 

Condensation in the tail light housing is normal and it is actually addressed in the vehicles owner manual. The issue is the LED lights do not create enough heat to burn the water vapors out of the housing like a regular light bulb. I was also worried when I first saw this and was surprised to see it mentioned in the owners manual! Now if there is an issue where its more than condensation and there is water standing in the housing I would then be concerned!

 

thats interesting, i didnt know it was considered normal. regardless, its pretty ugly.

that being said, now that its hot out i have a pool of water about halfway up the little circle things, maybe the dealer will be able to help me under CPO.

 

The book discusses headlight ccondensation in the "exterior light" section. I could have sworn it mentioned the rear lights but I could be wrong.

https://www.jaguar.co.uk/owners/handbooks-guides/xj-library.html

 

I also have a 2014 XJ and ONE of my rear lights has condensation - had it from new and as far as I recall, it has always had condenasation.

 

It affects 100%* of UK X351s because, as mentioned, the LEDs run too cool to evaporate the moisture. It has never been noted on any of my MOTs though, and I can't see why it would under the new MOT rules either so you'll be fine.

*+/- 1 car.

 

I have exactly the same problem here.
Both tail lights pick up condensation, no matter if I wash the car or not. It disappears for a while on a dry day, but then comes back again, especially after standing for a while under the direct sun.
I took them out to dry, but it never helped. The condensation came back the next day. I have no idea how to fix it, but I assume the reason are the micro cracks on the middle white part of the tail light. The problem is that this part is sitting ( glued ) inside the main red light, so it's not a one piece light, but rather a glued in part, which is odd to me. You can feel it when you move your nail on the stitching point between the white and the red part.
I assume there is nothing we can do with it except buying a new one.