Troubleshooting
Bulb failures caused by voltage surges have become more common as new vehicles have placed greater demands on factory electrical systems. The main lamp ground wire must be connected to the battery negative terminal or to a cable leading to it. If a voltage surge occurs, the bulb will look like it was struck by lightning! The metal base & glass will be burnt or the filament will blow up!
Prevent voltage surges by always starting the engine before turning on auxiliary lamps, and turn the lamps off before turning off the ignition (the latter is the most common cause of bulb destroying voltage surges).
Some moisture inside the lamp is normal. The lamp should dry out after a few minutes of operation. If not, check the following:
- The lens may be upside down. The lamp must be right side up so the vent on the bottom can drain.
- The lens/reflector unit may not be mounted tight against the lamp housing. Loosen, then re-tighten the screws.
- The gasket may be twisted or pinched. Some gaskets have a vent gap. Make sure it's on the bottom.
- Lamps with a "Snorkel" type wiring grommet in the back of the housing must have the opening facing down.