Is250 headlights dipped beam

[Bert320d]

Hopefully someone can help with this one. Factory Xenon lights in an Is250 sport, 06 reg with 63k. When ignition is switched on the lights function fine. Once the car is started the drivers side light goes out. Any help is greatly appreciated.

[Britprius]

27 minutes ago, Bert320d said:

Hopefully someone can help with this one. Factory xenon lights in an Is250 sport, 06 reg with 63k. When ignition is switched on the lights function fine. Once the car is started the drivers side light goes out. Any help is greatly appreciated.

The most usual cause of this is the bulb has failed. Often turning off the lights and back on will restore operation for a short while. Genuine Osram bulbs are around £80 each, but you can buy cheap HID bulbs from eBay for as little as £10 for a pair. A number of people here including myself have found the cheap bulbs to be fine both for brightness, and longevity.
It is possible the light ballast has a problem, but it is cheaper, and easier to change the bulbs first. You could change the bulbs from side to side, and see if the problem changes sides.

John.

[Bert320d]

 Should have mentioned that. I've changed the bulbs as well and it's made no difference, both still functioning perfect when just the ignition switched on but once I start the engine the drivers side goes out.

[Britprius]

Check you still have the 12 volt supply to the ballast when the light goes out. If the supply is still there the fault lies with the ballast. If there is no 12 volt supply the problem is in the wiring or relays for the lights.
The voltage to the ballasts rises when you start the engine, and this could be enough extra load on a faulty ballast to give the symptoms you are getting.

John. 

[madasahatter]

Probably all the rain has caused the ballast to fail. I believe they are under side of the head light, which isn't ideal really. Ballast are expensive but do last a long time.