2005 XJ8L: Weird things are happening with my headlights, but the strangest of all is that after a drive, water is dripping down the INSIDE front of the driver's right two headlights! I just had a water leak fixed - radiator replacement, reservor replacement, major hoses replaced (including the one inside the engine), and pressure tests show no leakage. If I leave the back cover off, then, it is normal. But when it is closed... drips go down, like you would see on a mirror after taking a shower in a bathroom with no ventilation. My mechanic who is well known and very good with Jaguars cannot find the problem and there are no water leaks when taking off the bottom pan, driving with AC off, then parking over clean white paper. ... no drip. anywhere, and the light not drip because it is in a watertight "box" with and airtight cap!. But again, if I leave open the screw-on cap, then it is fine. Note: Have had 2 mechanics look for this. HINTS?

 

Condensation would be my guess, if everything is all sealed, then what else is it likely to be???

 

The water tight box is not watertight-a common fault.

 

I had a similar situation as a result of water pooling inside the headlight assembly but out of sight. The only way I found it was to take off the bumper and then it was obvious .....my headlight fluid was too high!! I removed the headlight assembly and carefully emptied it of fluid and dried it with some gentle air from a hair dryer. The cause was a bad seal on access panel to the HID bulb (my fault for trying to replace the bulb without dropping the bumper---access is so tight I let the gasket slip out of place when replacing the cover)

 

If condensation has gotten trapped inside the headlight, it won't get back out. One time I had moisture get in because the bulb change cover had loosened. I had good luck removing the moisture by taping one of those little desiccant bags (the kind that come with clothes) to the inside of the bulb access cover. Closed it up and left it there a week or so and all gone.

Now, if your headlight housing is cracked, it will continue to get water inside.

 

The seals on the headlamp bulb covers move easily when you try to take the covers off, this causes them to get pinched and leak. What makes matters worse is any rain will run down the top of the wing ( fender) and drip right onto the offending cover with the trapped seal.

 

Replace the seals on the back covers.