HID BULBS HAVE CHANGED COLOUR.

Hid / Xenon bulbs lose their brightness with time, that is inevitable.

As the bulb ages over time and usage you will see the bulb(s) lose brightness and in some extreme cases the actual colour of the bulb will have a different hue. On some cars the bulbs look lilac / pink in colour and have zero benefits for the driver.

Simply change the bulb.

When changing the bulb, always do so in pairs. This ensures that the colour / output of the bulbs is the same.