School me on how headlights don't get moisture inside.

[Gasbuggy]

I just recently had the front end of my '06 Accord apart to put on a replacement fender, respray the bumper and some other parts.

I also sanded and cleared the headlights. I noticed on the top of each headlight housing, in a place you could never see or touch when in the car, there was a single small black rubber plug. A vent I'm assuming?

After I finished with them I pulled one of the plugs out in curiosity. They had clearcoat on them now. I put it back in but I don't recall which headlight since they were out of the car.

Within a couple days of putting the car back together I had moisture in the driver headlight. The moisture has been getting worse.

I'm not sure if it's the one I pulled the plug out of or not. But let me tell you what a pita it will be to remove one headlight. The front bumper will have to come off, I managed to put the car back together without scratching any of my fresh paint.

Can I drill a small hole somewhere else in the headlight housing and somehow recreate what it naturally had functioning before? For all I know the plug I bothered with is the one with moisture.

Kind of funny to me, since I just did paintwork on the car my friends/family are interested in looking at it and now it's got this screwed up headlight so that's the focal point.

 

[FT92]

I still drive a 99 accord and the driver side head light used to get moisture in there, I watched a YouTube video on how to dry it inside then reseal, it's been three years now and so far, so good. I know what you mean about being a pain to remove head lights, even my 99 is no walk in the park.

 

[alcyon]

I still drive a 99 accord and the driver side head light used to get moisture in there, I watched a YouTube video on how to dry it inside then reseal, it's been three years now and so far, so good. I know what you mean about being a pain to remove head lights, even my 99 is no walk in the park.

I guess thats when they changed the design to be a PITA to remove, My 89 Soarer headlight is easy to remove from above.

 

[SHOZ]

Every headlight I have seen has a bent rubber vent tube. The heat of the bulb should force out the moisture.

 

[JHZR2]

Every headlight I have seen has a bent rubber vent tube. The heat of the bulb should force out the moisture.

Right. I’d run the lights as much as possible to get the moisture out.

A rubber plug either works or it doesn’t… maybe it wasn’t reseated properly?

 

[Pew]

Every headlight I have seen has a bent rubber vent tube. The heat of the bulb should force out the moisture.

Makes sense why my friend's BMW turn signal part of the housing has moisture inside it....

 

[proveitwithdata]

bmw 7 series with the new alien face actually claims moisture is normal now

 

[Vern_in_IL]

Simple chimney effect.

Light source heats, air rises, so all you need is a low intake of cool DRY air, and a higher exhaust of warm moist air. Volla, headlights stay dry.

Most systems have a filter behind a rubber plug, at the intake, if this filter gets full of dust, then the air flow will decrease,, or if the intake is in a wet location, it will draw moisture into the headlight. Other lamps just use a Gore-Tex patch and no moisture removal function.

 

[Hall]

Right. I’d run the lights as much as possible to get the moisture out.

One of mine got moisture inside and a combination of outside temperatures, me not driving much or something, it wouldn't go away.... So I put a heating pad on it for a couple hours. It worked !

 

[Audiman]

Put a desiccant bag in the back of the drivers headlight. Like what you get in the box with a new pair of trainers but a bigger bag.

 

[Gasbuggy]

I run these lights heavy all the time. Half my driving is at night, and I have the low beam modified so a 9005 is in there too. 30 minutes a day of lights on. Initially, it seemed like the moisture was clearing from the lights being on, but it's gradually building up. Seems to show up after the lights cool back off.

 

[Gasbuggy]

Simple chimney effect.

Light source heats, air rises, so all you need is a low intake of cool DRY air, and a higher exhaust of warm moist air. Volla, headlights stay dry.

Most systems have a filter behind a rubber plug, at the intake, if this filter gets full of dust, then the air flow will decrease,, or if the intake is in a wet location, it will draw moisture into the headlight. Other lamps just use a Gore-Tex patch and no moisture removal function.

Thank you for this post. That explains why that vent was at the top part of the headlight assembly.

I describe Hondas plug as maybe something similar to an earplane if you've ever seen one. Kind of a one-way valve plug.

 

[SHOZ]

Right. I’d run the lights as much as possible to get the moisture out.

A rubber plug either works or it doesn’t… maybe it wasn’t reseated properly?

I had a spider nest in one of the vent tubes once the clogged things up.

 

[vavavroom]

If there's a constant moisture/condensation problem with a headlight, and if the vents are not clogged, the lens gasket is shot or there's a crack somewhere. Headlights with Lexan lenses have the lenses usually glued to the housing with XXXX cement/sealant. Many people replace the XXXX adhesive with silicone to reseal a headlight but I would not do that. Best to use the XXXXX. On a new car I add an external bead of sealant where the lens and housing meet. I use YYYYY for that. No problems in many years.

Vents on the OE Mini halogen housings.

Air inlet at the bottom of the housing. The vent is located in the square recess.


There is one air outlet on each side of the housing near the top facing the firewall. The vent terminates in a short length of rubber tubing.


On new lights, I add a bead of sealant that overlaps the housing and the side of the lens by 1/4" for the purpose of redundancy. So far it has worked for me.

 

[Gasbuggy]

It's possible that all the man handling and sanding might have affected a headlight seal.