Introduction: How to Solve Moisture or Condensation Issues in Your Lights

By 4DIYers
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Video tutorial on various tips and tricks on how to solve moisture issues with your lights. This includes headlights, taillights, marker lights, fog lights, etc. Excessive moisture or condensation in your lights not only looks bad, but it can cause the reflectors to peel, reduce light output, and may eventually result in pooling water depending on the cause.

Supplies

  • gaskets
  • clear sealant
  • socket and ratchet set
  • screwdriver set

Step 1: First Example Using a Tail Light

I have both condensation in my headlight and taillights. Starting with the taillight, the issue is between the center light and reverse light. First is removing the light, it’s held on with two bolts which are located on the tailgate side. Light removal procedures will vary based on your vehicle.

Lights will have a seal around the outer edge between the lens and housing. This is some form of an adhesive that can typically only be separated by heat. If it’s a classic vehicle, then it may have an easily removable lens. Heat can be used to separate the lens and housing, either by a heat gun or by putting the light in an oven. Then the light can be resealed if this is the problem.

Step 2: Solving the Moisture Issue

Lights typically have a vent located at the top, this light has a little snap in cap. These vents can become plugged or they’ll be missing their cap. Ensure it’s not plugged by using a vacuum cleaner with a little pick. If the cap is missing, then replace it as needed.

Removing the bulbs, their particular light has a circuit board on the backside, this is held on with phillips screws.

Once removed, there are rubber seals for each of the bulbs. Other types of bulb retainers will also have some form of a seal, this can even include an o-ring. Inspect the seals, make sure they are present, free from deterioration or damage, are soft, and are clean.

Looking through the bulb holes, you should be able to see the condensation on the lens inside. If there’s any volume of water, drain the light. For condensation, simply leave the light open without the bulbs installed, lens facing down so the bulb holes are up, and place it in the sun where it can evaporate. This took a couple of hours for me on a cooler day.

Step 3: Once the Moisture Is Gone

And as you can see, the moisture is now gone. We’ve had quite a bit of moisture lately due to hot and cold cycles and rain, so I’m assuming the condensation just formed due to the difference of temperature between the interior and exterior of the light. This is the only time I’ve had issues with this light.

Reinstall the light in reverse of removal, making sure those gaskets around the bulbs are properly seated during the process.

Step 4: Second Example Using a Headlight

For the headlights, I had a small amount of condensation which was caused by restoring the faded lenses. During the wet sanding process, a small amount of water managed to get inside.

Removing the light just like before, there are only three fasteners that hold it into place. Then pull the headlight assembly out.

Step 5: Removing the Moisture

On the back, just light the taillight, there will be seats and rubber grommets around the bulbs.

Again there’s sealant between the lens and rear assembly.

I wasn’t able to find the vent holes, however, there is a small access hole on the top with a tape-like cover. And as you can see, the adhesive seal seems to be broken on one side.

Again just remove the bulbs and let the light sit for a period of time until the condensation evaporates. Another option is also turning on the lights for any very light condensation, the bulb doesn’t necessarily need to be clicked in, just make sure the bulb isn’t against the case where it may melt the plastic.

Step 6: Installing the Headlight

Do not fill the light with water to find a leak, as mentioned earlier, water can damage the reflector. If you have a way of applying compressed air to the lights, this is an option. Then use a soap and water mixture in a spray bottle, apply it to any seams or sealed areas, and look for bubbling.

If the seal is gone between the lens and housing, a clear sealant such as silicone can be used around the perimeter of the lens and housing, however it may not look good. Another option is purchasing a used or new replacement.

Step 7: Replaceable Seal Type Assembly

As an example using lights from an older vehicle. This will vary based on the vehicle but does provide a great example of what a light that’s glued together consists of. The reason for the removable lens is to change the bulbs without needing to remove the entire assemble. The lens is only held on with four plastic thumbscrews on the rear.

Step 8: Replaceable Seal Type Assembly

Once those thumbscrews have been removed, then gently push out the lens. If it hasn’t been removed for a while, then it’ll most likely be stuck in place.

As you can see the gasket is stuck to the lens and has a groove where it fits into. The dealer may carry a gasket replacement or you may be able to find a generic type gasket that fits this application.

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