One of the biggest problems with headlights is the intrusion of moisture into the headlight assembly. Condensation that is trapped within the headlights can quickly discolour and cloud up the inside of the headlight, effectively reducing nighttime visibility while shortening the life of the headlight bulb. The following steps can help eliminate and prevent future instances of headlight condensation without the need for costly kits or professional services.
Remove the headlight assembly from the vehicle. Disconnect the electrical connectors at the back of the headlight and pull the headlight itself out of the vehicle. The method for removing the headlight varies depending on the vehicle, but the most common tools needed for removing the headlight are a Phillips screwdriver and a ratchet with the appropriately sized socket.
Remove the socket and headlight bulb. Wipe away any moisture on the outside of the headlight with a shop towel. Lay the headlight face down and dry out the inside of the headlight by aiming a hair dryer through the headlight socket. If water is trapped inside of the lens, you may have to use a drill to create a small hole through the bottom of the headlight assembly or if possible, tilt the headlight and allow the water to drain through the socket hole.
Inspect the headlight assembly for any cracks or holes that can allow moisture to enter the headlight. Small cracks can be patched up with an application of clear urethane sealant. Large cracks and holes may require replacement of the entire headlight.
Apply Teflon tape to the seal around the headlight bulb socket. Make sure the application of the tape is thorough and tight. The tape will prevent moisture from entering the headlight through cracks and gaps within the rubber socket seal.
Replace the bulb and insert the headlight assembly back into the body of the vehicle. Reconnect the electrical connectors and test the lights by turning them on.
If your vehicle uses sealed-beam halogen headlights, the best solution is to simply replace the entire headlight. Sealed-beam units are relatively cheap and can be found in most automotive parts outlets.