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Repeated condensation

Ok I have a 2011 Cadillac and have a problem many have with thier car. My passenger side headlight has come down with condensation. Today I drove around in the daytime with the high beams on and most but not all evaporated. But a few hours after I got home and the car sat for a while I could tell it was coming back.

My question is if the headlights being on dried it up then why is it coming back? Would driving for a number of hours with the high beams on dry it out more?

All headlights have vent tubes to allow condensation to escape.

Make sure these vent tubes aren’t plugged with something like a spider web/egg sacs.


You probably evaporated what’s in there, but it condensed again when cooled down.

To really get it out, you need to remove the bulb and circulate lots of warm air in and out at the bulb opening, like with a hair drier. Now how did the moisture get in? Poor seal around the bulb? A crack or poor plastic weld in the headlamp assembly?


I would love to be the idiots who designed this Cadillac made it near impossible to do that. You have to remove the entire front bumper. Back in the spring I had to replace the headlight bulb, it cost me almost $300 to do it due to all that is involved in getting to the bulb. Car makers are idiots.

You won’t be happy when you hear what it will cost to replace that leaky headlamp assembly.

Did you choose this car because it appeared to be designed by idiots or because it was appealing?

The part isn’t bad as it’s online for $150, the big cost is the labor. Car choice was based on finance and comfort

Before you waste your money replacing headlight assemblies, read this.


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After repeatedly drying out my own car’s headlights long ago I got disgusted and drilled a small ~1/8" hole at the top center of the white housing adjacent to the clear lens and another hole at the lowest point in the plastic housing and never saw water accumulate again. When customers had complaints of the same problem I offered to drill theirs and many chose to, most were happy with the results, none ever complained that the problem got worse. When all else fails I try basic common sense and a hole at the top to vent and a hole at the bottom to drain and allow a draft to occur seemed worth trying and I always suggest doing so as a last ditch effort before spending Hundred$ on replacement. housings.


@Rod_Knox, I did something similar on my sisters car years ago. Some type of 70’s era Plymouth sedan-do not remember the model. Water was always accumulating in the rear tail light assembly. Lots of sealer etc did not stop it. So I drilled a 1/8" hole in the bottom and the problem went away.

Yep, water is in air all the time. The lower the temp, the denser the air and the less the air can hold the water and it condenses on the surface. When the air heats up it can hold more water without condensing. That’s why airplanes can take off faster in the winter than summer but that’s another forum. But yeah, if drilling holes fixes it, why not?

Duct tape back on mouth.

If it is condensation from humid air both headlights should have water in them and perhaps most other cars in the area.

I see water in headlights here in the desert, the humidity is 8%, water leaks into them when going through a car wash. There have been warranty extensions on some vehicles headlights because of water intrusion.

Drilling holes in the lamp housing might work in some areas but where I live the headlights would cloud up with dust in a few years.