The control unit with code W3T12671 is a xenon headlight control unit (xenon ballast), used on several cars, including many Mitsubishi models and some vehicles from other brands (such as Peugeot, Citroën, and Chrysler) that share components.

What is the W3T12671 control unit used for?

• Xenon headlight ignition and operation control: regulates the voltage required to turn on and maintain the xenon lamp.
• Light stabilization: maintains constant brightness without flickering or switching off.
• System Protection: Prevents overloads, short circuits and electrical faults related to the headlight.

Why does it need to be changed?

The W3T12671 control unit should be replaced when it is faulty or malfunctioning, and the most common symptoms are:

• Headlight that does not turn on at all, even after replacing the xenon bulb.
• Continuous flickering of the headlight while driving.
• The headlight turns off a few seconds after being turned on.
• Dashboard lights error.
• Burning smell or burn marks on the control unit itself.

In these cases, the lamp may still be working, but without an operating control unit it cannot turn on properly.