When too much is too much

Every now and then, even state-of-the-art xenon headlights may mist up from the inside after a visit to a car wash or driving on one of those particularly damp and drizzly days in November. But that’s generally not a reason to worry. After all, today’s car headlights are equipped with a ventilation system, i.e. they are deliberately designed to “leak” – so that, for example, any moisture that has penetrated them can escape again on its own. However, if the headlights do not dry out again, the seals should be checked and the ventilation slots cleaned. Too much moisture is a major cause of problems with the integrated, highly complex electronic components. These include the driver and power modules, the latter also known as the ballast.

The power module has the task of igniting the inert gas mixture in the lamp with a high-voltage pulse of up to 30,000 volts. It ensures that the spark between the electrodes is ignited; it then regulates the lamp output to a constant 35 watts. The module draws the required voltage from the vehicle's electrical system via a DC/DC converter.

The driver module, on the other hand, controls the electric motors for the adaptive driving lights (“up/down” and “left/right”) and the LEDs for the parking lights, low beam and turn signals.

Both modules can fail due to processing errors, strong temperature fluctuations, insufficient operating voltage, defective electronics in the unit, internal short circuits or even due to moisture penetration. Here, too, AIC offers 25 different power and driver modules for 6,100 applications, respectively, as great value replacements.

Please note: Driver modules may need to be initialised or “trained” to suit the vehicle. Always follow the manufacturer’s instructions in the repair guide.