I bought my 2006 RX 400H two months ago and it has headlight condesnation problem since day one (driver side). I check online and can't really find any helpful information. Most of the people has it fixed under warranty but unfortunately mine is out of warranty therefore I decide to try to fix it myself before spending thousand dollar on a new one.

first, you have to take out the headlight assembly, there are totally 4 bolts you need to loose up and also you need to take out part of the bumper in order to slide the headlight out.

Here is the look of the headlight from the back:


Once you take it out, you will be able to access all the light bulbs. I found that almost all the rubber O-ring on the bulb socket were cooked. See the picture below and you will understand what I'm talking about. I believe that's where most of the mostiure/water get in the headlight. I bought my new O-Ring assortment from Harbor Freight. 20 bucks for the whole box.







Once you replace all the broken O-Rings, you might want to try to seal the assembly along the cover with outdoor silicon to stop the water leaking in from the side. Remember to tape it first, you don't want the silicon to ruin the cover. You will see a gap between the lens/cover and the assembly body. Just fill up that gap and wait for it to cure.






While you waiting the silicon to cure, use the hair dryer to dry up all the mositure trap inside.



And that's it !! put the headlight back in carefully and don't wash the car for couple days to let the silicon fully dry. My headlight doesn't have any condesnation problem since then and I believe the fix is fairly easy, everyone should be able to finish it within hours
Good luck!!

Cheers,
Derek Chiou

 

Good post. Lots of good pics and helpful info. Hope this is helpful to the "hands-on" types in here.

::-)

 

Change the bulbs while your at it.

 

I am not sure if it's the O-ring or the extra silicon job fix my problem.
but it's been heavily rain for the last couple days and the headlight still intact. FYI.

 

Hey nice write up! Thanks for sharing, glad someone has a problem solved by themselves. Good job!

 

Hi Derek, does your RX have the headlight washers? Was wondering if that complicated things when taking off the bumper. I'm planning to do this as well. I tried doing it the other day based on Mandyfig's DIY post (which is equally helpful), but I wasn't able to take the bumper off. And I noticed that his headlight housing does not have AFS, and looking at yours, seems like you have AFS.

I'll try again tomorrow using yours combined with Mandy's DIY instructions. I am not really experienced with tinkering with my car, but man, this condensation is really ticking me off. Can't go to the carwash!
-Pete

 

Does the condensation affect the brightness of the headlights at night when driving?

I don't do a lot of night time driving, so was curious as to whether anyone has noticed a problem with it.

I dislike the appearance of the condensation, but if the brightness is affected, that would get me more motivated to fix it.

Thanks.

 

I dried it whie it was mounted with new O rings and it worked just fine