In one of my headlights I have a moisture problem.
Is it save to bake the unit in an oven (100 degrees) or is it better to use a hairdryer ?

Thanks,
Paul

I would probably go the hairdryer route as you have less of a chance of damaging the headlight. You also have more control over what is going on rather than watching how it is baking in the oven. Joe

Joe,
this was the first time I opened the unit. I decided to use the blower because I think the whole unit needs reallignment if I remove it to put it in the oven....

The blower is now blowing for 15 minutes and the moisture is already disapearing!

Seems I was to quick posting my question

Thanks!

The bigger issue is keeping future moisture out. There is a seal where the glass mates with the reflector and another seal where the bulb mounts to the reflector assembly. The bulb seal is an easy one, if it's bad, missing or damaged replace it. The seal between the glass and the reflector can be resealed by masking the glass and the reflector assembly and a thin coat of RTV. The back side of the bulb is fairly well protected so more than likely it's the seal at the glass mating surface.

Especially the bottom edge of the headlight glass/unit interface.
When the headlight is in the 'retracted' position, the bottom edge becomes the leading edge that gets hit by high pressure air at speed.
At least that's where mine leaked. Fixed with some clear RTV sealant.

Jim gave good advice on the masking the lenses/reflector .
I think that a better sealant to use is honda bond #4 on the mating surface edge, this semi permeable sealant will get semi hard and not peel off like an RTV will .
Just clean the glass edge with some alcohol and let it dry.
I use blue painter tape to get the bond line close to the lens/ reflector joint, the Honda Bond seems to be able to be poured out of the tube, a little dab will do
The gray sealant blends rather well with the lens/glass interface.
I have fixed more than a few leaking light assemblies with this stuff and it looks factory if you dont make the masking area too wide

I used an old scuba snorkel, too off the mouth piece and shoved in where the bulb plugs in. On the other end, I inserted a funnel and place a fan in front of it. Left it running over night and all the moister was gone in the morning.


Eventually, this drove me to purchase new lens so I have two in storage that are ‘repairable’. I’ll have to try these sealing suggestions.

There was some kind of powder (white) on the rubber seal. This powders was also in the reflector and on the H4 lamp itself....
I cleaned the whole thing, used the hairddryer to remove the moisture (30 min.) and reassembled the whole thing.
I concluded that if this powder could enter the headlight moisture also can get in.
I hope the removal of the white powder solved the problem. I think it does.

Thanks,
Paul

the white powder was corrosion.
You will still need to reseal the edge of the lens to the edge of the reflector this is a bead around the outside of the headlamp where these two parts are joined