Removing the Perspex face from headlight module

The Ballast stops your vehicle from becoming cross eyed.OOPS,Im treating members like simpletons again,who would have thought:D:D:D:D:D:D:D
Sorry,not having a dig at you.
The ballast amplifies the power to power the bulb.
Andrew

Ok thanks that makes sense ....booster rather than ballast might be a better name ......but then maybe to an electrical engineer ballast has a different meaning ........

Wonderful site this ........always an answer to those little perplexing questions on life ..and land rovers .......which can at times be a thing of great mystery to us technically challenged types .......

For HID's they are a controller and ballast in one, i.e. arc initiator then as the arc is established the resistance drops it then controls the current so the bulb doesn't burn itself out.