How to find a leak in a foggy car headlight (Dodge Grand Caravan)

Warning: loud vacuum cleaner sound in the video!
Here is a short video showing one way on how to find where is the leak allowing the water ingress into a car headlight. The first step is to remove one of the light bulbs, and blow air inside of the headlight. Use soapy water to spray around the seams. Mark the area producing bubbles. Dry the headlight. Reverse the hose on the vacuum cleaner to suck air out of the headlight. Reduced pressure will dry the headlight. Use the sealer on the cleaned surface of the headlight seam where it was bubbling.