Headlight Condensation Issue

[Ompa]

Car: 2008 GS300 
Issue: Heavy condensation in one of the headlights (passenger side). Especially after washing the car or after heavy rain - a lot of condensation would appear in both headlight housings on one side.

Picture below: To the left is the affected headlight, to the right is the unaffected one.

I've seen multiple threads where this issue has been discussed, so I thought I'd also write about my troubleshooting journey.
 

1. Condensation appears in the passenger headlight. After a couple of days (depending on the weather) it would reduce, but very slowly. This needed fixing.

2. Removed the bulbs from the headlight and let it sit in the sun for a while. This would remove the condensation after about 60 minutes. However, after raining or washing the car the condensation would appear again. Not fixed.

3. Decided to remove the headlight from the car. This is a very easy task in itself since the headlight only is held on by three bolts, see exploded view below:

However, to reach these three bolts the front bumper will need to be (partly) removed. This might look hard - but is in reality quite easy. A rough description is as follows:
     A) Remove engine plastic covers, disconnect Battery
     B) Remove 10mm screws under the car keeping the bumper in place
     C) Remove 7 10mm screws on top of the bumper, 3 by each headlight and one by the Lexus logo
     D) Remove plastic clips and screws by each wheel liner, so a hidden screw holding the bumper in place can be accessed
     E) Gently slide the bumper out - there are "tabs" close the upper fender holding it in place so make sure it can slide out from these
     F) Disconnect the washer, and connector for main harness connected to the headlight(s)
     G) Remove the aforementioned 3 screws holding each headlight in place 

Note: The headlight(s) can be removed without fully removing the bumper, see below:
 

 

4. Took the affected headlight inside, removed all the bulbs and then lit it sit overnight to ensure no moisture was left before getting to work at it. 

5. Added silicone to the original seal.

6. Assembly is the reverse of disassembly 😃 Take note with the main harness connector - it's easy to think "Ah there I got it on" when in fact it's not fully engaged. Don't ask me why I know this...

7. Live a trouble-free life with a headlight not affected by condensation? Unfortunately, this was not the case. Condensation still returned despite my efforts in sealing the headlight. Not fixed.

8. So I bought a dehumidifier and placed at the bottom of the headlight assembly, as a temporary solution.

Did this solve the condensation issue? Yes it did. So the problem is as of now temporarily fixed.

9. I'm currently debating whether step 10 will be either:
* Remove the headlight again and look for issues with the "built-in ventilation" for headlight
* Buy a new headlamp

Lexus Sweden charges 8700 SEK (765 £) for a new headlight, but I've also seen aftermarket versions available on e.g. eBay. If anyone has any experience with aftermarket headlights for the GS I'm all ears 😃

TL;DR: I tried fixing a headlight condensation issue on my 2008 GS300, but only managed to temporarily fix it using a dehumidifier placed in the headlight assembly. Hopefully someone will benefit from my troubleshooting journey nonetheless though.

/ Chris

[tk1692]

My 2008 GS450 is plagued with the same issue on the same side.

Heavy rain -> condensation -> HID ballast blown. This has LED to the costly replacement of the HID ballast three times (!). The design of the assembly is poor in that if water gets in there at all, the ballast gets soaked.

I tried the dessicant packet idea as well but it's not going to work.

I noticed the rubber seal/weatherstripping at the edge of the engine bay over the headlight assembly is discontinuous, perhaps due to age, so I sealed it to prevent water ingress. I just used Gorilla tape at first, then some new weatherstripping. I can't guarantee you have the same issue but maybe worth having a look. So far so good for me anyway.

 

[Ompa]

Update after 1 year

The "solution" with the dehumidifier described above worked like a charm - for maybe two months. Then the problem reappeared again, probably due to the dehumidifier needing a recharge or to be replaced. So it clearly was not a permanent solution. 

I still haven't come around to removing and reinspecting the headlight regarding the "built-in-ventilation". However I have tried another "solution" regarding ventilation for the headlight.

1:

I drilled five small holes in the inspection cover located at the back of the headlight.

2:

I then installed a dust filter behind the cover to prevent small debris from entering the headlight.

 

Conclusion:

So far this method seems to be working, since installing the updated cover no condensation has appeared in the headlight. Will update again regarding the longevity of this solution.

/ Chris

[Malc]

2 hours ago, Ompa said:

Conclusion:

is this the effect of the heat from the lit bulb allowing evaporation of ( potential ) condensate thru' those tiny apertures then ?

Malc

[ColinBarber]

Not a Lexus but method is the same for checking/fixing a poorly sealed unit: