Instructions on how to de-fog your headlights:
1. Remove ALL of the bulbs and wiring from the headlights. Not doing so will cause severe damage to your headlight housings, forcing you to purchase yet another set of headlights.
2. Heat your oven to 250 degrees and sit a piece of WET cardboard on top of a plate.
*Note - placing the headlights in the oven are to speed up the evaporation of the water. If you are not comfortable with this step you can place the headlights in direct sunlight, but it will take longer for the water to evaporate.
3. At 250 degrees place the headlight on top of the cardboard for 3 min (Note: It is NOT necessary to pre-heat the oven for this process).
4. Remove the headlight from the oven (careful, it will probably be quite hot) it and push your Mustang headlight back together as much as you can. Our headlights are sealed front to back, so push as hard as you can on the front and back housing to create a better seal. Try your best not to have any openings between the housings.
5. Once pressed firmly together, take some silicone RTV sealant, which is available at any hardware store, and spread it along the line where the housings come together. This step will cover any open holes left over from any silicone not drying in place completely.
6. Let the freshly applied silicone dry before re-installing the headlights into your Mustang.
This process does melts the silicone glue that the factory used to seal the housings. Sometimes the glue has open spaces left over after being sealed at the factory. As the silicone glue dries, it re-hardens and is pressed tighter between the two headlight housings, creating a stronger bond. Adding more silicone glue is necessary to cover any other possible gaps in the headlight housing so that another leak does not develop
7. You will also want to check the seals around the Mustang headlight bulbs as well, to make sure there is no extra air leaking into the headlights from the bulb housings.
How to Seal your Ford Mustang HeadlightsAutoHow.tv, AmericanMuscle's video sponsor - http://www.autohow.tv/node/31