Fog lights should be mounted on the lower half of your front end. Somewhere on or below the bumper is ideal. They should be around 10 to 24 inches above the ground or at least below your vehicle’s headlights. But with fog lights, lower is better. Since fog usually starts about 2 feet off the ground your fog lights should be below that. If they are higher than the fog the only thing you’ll see when you turn them on is the reflection of your lights in the fog, which is reflected back into your face, making things worse. Kind of like when you hit your high beams in heavy fog. Mount your fog lights under the fog and you’ll be able to see the road ahead.
Tools Needed: Measuring Tape
NOTE! Never use fog lights with high-beam headlamps or auxiliary driving lights as this can blind oncoming traffic.
STEP 1. Park your vehicle on a flat surface with the lights shining on a wall 25 feet away. Not 20 feet. Not 30 feet. It’s got to be 25 feet away for the measurements and lights to come out properly.
STEP 2. Now measure from the center of the fog light lens to the ground. Go put a visible mark on the wall at that exact height.
STEP 3. Adjust the fog lights so they are facing straight forward and the top of the beam is about 4 inches lower than that mark you made on the wall.
This should allow the beams to cut right through the fog like they are supposed to.
The quick answer to this questions is no. Condensation buildup inside a fog light assembly is normal, and it occurs for a number of reasons. First, vents along the top and bottom of the fog lights housing are necessary to equalize pressure differences that would otherwise cause the entire assembly to crack and fail. Hot fog light bulbs create high pressures inside the fog lights assembly, and temperature differences only increase as lens cover surfaces cool from direct airflow contact at speed.
Condensation does not mean that a fog light assembly is defective, and the presence of fogging or misting due to condensation is not considered a valid reason for warranty replacement of the entire fog light assembly.
If water collects inside your fog light to the point where puddles form, odds are you've got a cracked fog light lens cover or assembly. This is a problem, and must be addressed.
After hot, pressurized air has worked its way out of the fog light through the vents, humidity can get drawn in from the outside. So, fog lights that have been on during hours of driving become fogged on the inside because their cool temperature creates a low-pressure area that actually draws moisture in. This condition is made worse by high outside humidity, and by colder outside temperatures during winter months.
Condensation inside the fog light assembly can also occur in other situations such as a car wash. And it can occur even when fog light bulbs are not turned on. For example, a car that's been driven in the daytime and parked can develop condensation as residual heat leaves the engine and warms the back side of the fog light assembly.
While most condensation in the fog light lens usually dissipates after approximately 20 minutes of driving with the low beams switched on, some small and insignificant areas of the lens may remain misted for a little longer. A normal amount of water condensation inside the fog light assembly will not affect the optical functions of the fog light in any way, and will not cause any parts or wiring to corrode. To minimize condensation buildup inside the fog light, make sure any dust boots or covers are on tightly. Also make sure that the fog light vents are not blocked, which could prevent condensation from escaping.
If water collects inside your fog light to the point where puddles form, odds are you've got a crack in the light lens cover. Water can also leak in because of improper seals around dust boots where bulbs are inserted. If no cracks or holes are visible around the edges of the fog light, the problem could be the housing itself. If you can visibly locate a crack, it's best to repair it with sealant.