Even if your car is not that old it is possible to get condensation in your headlights. I once had a Mazda Tribute that had headlight condensation in both headlights within one year of purchase! What can you do if your car is not under a factory warranty and you start seeing headlight condensation? Luckily there are a several viable options for those that are willing to DIY.
Most car headlights are composed of two pieces, the main assembly used for mounting to the car chassis and holding the bulbs, and the lens. The two pieces are held together with butyl rubber glue. This glue can break down and this allows the condensation in headlights to occur.
Before you start you will need to purchase replacement butyl rubber glue. Once you have that in hand you can get things started. To loosen the original glue and separate the two pieces all you need is a little heat. There are two ways of going about heating the glue to allow you to separate things; bake the headlight housing at 250 degrees Fahrenheit for 15-20 minutes or use a heat gun to heat the sealed area. If your oven is large enough to accommodate the headlight I prefer this method as it provides even, consistent heat compared to a heat gun.
Once the butyl glue is heated you will then carefully separate the two pieces. Take your time and apply gentle, even pressure as you pry the two pieces apart. Now, place both pieces back into the oven for five minutes to soften the glue again. Remove the two pieces again and place the new butyl glue around the edge of the headlight housing where the two pieces seal together. Be sure you do not leave any gaps when you are putting the new sealant into place. It is not necessary to remove the old sealant for that step, just heat it up so that it is soft enough to be pliable. Use extra care to not allow the sealant to ooze into the headlight. This will give an unsightly appearance and could affect the headlight beam pattern and limit the headlights effectiveness.
Once the sealant is in place just line up the two halves and squeeze them back together. Use some small clamps in an area that that will not damage the lens and set it aside for 30 minutes to one hour and you are ready to reinstall the housing in the car. Once dried, you can use a hobby knife to trim any excess rubber glue from the outside of the headlights. If the only clamps that you have available to you are metal you should put a couple layers of painters tape on the clamps to further prevent damage to the headlights.
The second option that costs a bit more than baking your headlights is a set of aftermarket headlights. These tend to cost a lot more than OEM housings, but are prone to fitment issues and are often much lower quality. There are some decent deals out there that are solid quality at an affordable price. This is also a way to add a custom aspect to your car to set it apart from every other car on the block. There are many options for these aftermarket housings to be found on various sites around the web and expect to pay between $50 and $200 per side.
The last and most costly option is to replace the headlight housing with one from your local dealer. Depending on the car that you drive these can cost several hundreds of dollars; so, for most, this is the last one their last option. You could save yourself some money and get the housing assembly from a junk yard, but you would have to find one available and you could end up with another leaky housing. Even worse they could have hazy lenses. You could still come out ahead if the lens is hazy, but sealed well. Check out my pages on how to restore your headlights and headlight restoration kits comparison to solve that problem.
All of these options require you to remove your headlights which can be quite a task depending on your car. You may want to get a repair manual for your car to assist you with this task as it can sometimes be quite involved. But, don’t let that deter you; most anyone can follow these steps and remove the condensation in your headlights. You will find that the bit of work will be worth it for the money that you will save by doing it yourself.