HID Headlight/CONDENSATION

Make sure the back plastic cover is on tight. If it is tight then you make have a crack somewhere or the last person that removed the cover did it on a very humid day.

The only real solution is to remove the headlight assembly, seal all of the edges then reinstall it on a nice hot day.

 

It should be cover by warranty..mine was...it was doin the same thing at the same mileage...toyota extended the warranty on the HID headlights. Go to the dealer and they will replace the entire assembly...they did for me

 

Never noticed or seen this problem and I'm past 57K miles.

 

Old post but thought I’d document what I did today to resolve my condensation issue on drivers side headlight.
First, 2006 Prius, new headlamp assembly installed 2008/9 so well past any warranty period.

Sorry no pics.

First removed the cover over cross member by removing 6 push pins.
Remove top 10mm bolt at top of headlamp assembly, already accessible.
Then removed 3 push pins and 2 screws holding bumper at top of grille.
This enables you to get at the second of three 10mm bolts securing headlamp assembly.
Removed 2 push pins in wheel well of drivers side front.
Once you pull back inner wheel well cover, you can access 10mm bolt that holds bumper.
Once this is done you can pull back the bumper a few inches to get at the third and final 10mm bolt that holds assembly. It is located at the bottom of drivers side quarter panel. It’s the 10mm found under the black plastic piece that has 2-3 screws. I removed these too, but don’t think I needed to.
At this point get a second set of hands to pull bumper away from car enough to pull out assembly. Be careful here as assembly is still attached to several plugs/wires. However, you are still able to rotate assembly enough to clean along the entire seam of the headlamp. I removed the three Phillips screws holding a positioning plate to be give better access to seams.
I then took a can of black Flex shot (yes the kind seen on commercials) and ran a bead around entire length of assembly, taking care to run my finger along seam and ensure it got into all the crevices. I allowed to cure for a few hours and then reassembled everything.

I will continue to monitor over next few weeks as rain and hand car washes put this to the test. I found after hand washing car I would get condensation in headlamp so I will wash next weekend and observe. My only concern is heat found in engine compartment as I’m not sure Flex seal can withstand high temps. We shall see.

I didn’t bother documenting with pics as I think as long as you are handy enough to move carefully and with some common sense you should be able to perform this. I don’t mean to belittle anyone attempting this, just proceed carefully and don’t drop any bolts/pins.

Total time, ~3 hours
Tools, screwdrivers, 10mm socket, pliers, Flex shot ($12)

If anyone has any other ideas or comments, feel free to add to this thread so we have some data for future Prius owners as I suspect this issue will only become larger with seals failing in our aging cars.

Thanks!