Some moisture accumulation inside a vented headlamp unit is normal. This normal moisture will appear as a fogging on the inside of the lamp lens, similar to the fog that sometimes appears on the inside of a windshield. This moisture may be removed by activating the headlamps on HIGH beam for 15 minutes.If water droplets larger than 1 millimeter (0.039 inch) in size have accumulated on the inside of the lamp lens, the headlamp unit should be replaced.