If water is getting into your headlight assemblies on your Nissan Quest, you need to repair them at once or risk having an electrical failure in the assembly. Fortunately, repairing a water leak is a rather straightforward task on a Nissan Quest. Unlike many vehicles, the Nissan Quest was designed so that the front end allowed the headlight assembly to be removed without needing to take off the bumper. For this reason, expect the whole job to take less than an hour.
Turn off your Nissan Quest and prop open the hood.
Remove the bulkhead, the large rubber covering over the grill and headlights, by removing the two bolts on either side of the grill and the fasteners along the ends that cover the headlights.
Remove the three bolts mounting the headlight to the vehicle.
Reach behind the headlight unit and disconnect the wiring harness.
Pull the headlight unit off its mounting bracket. Use the screwdriver to pry on both sides of the headlight if it is stuck.
Set the headlight on a table or the ground and remove the headlight bulb through the rear weather collar.
Dry the inside of the headlight assembly with a towel or leave it in the sun for a few hours.
Apply a bead of silicone sealant over the crevice between the headlight lens and the headlight housing. Look around the housing for any cracks where water may enter and seal them.
Replace the headlight bulb in the headlight assembly. Put the weather collar back on and seat the assembly on the bracket. Mount the three bolts to secure it. Plug it back in the wiring harness and replace the bulkhead.
