What are D1S bulbs?

What are D1S bulbs?

OEM (factory installed) HID headlights have a D-series naming system. They are named using 3 characters, like ‘D4R’, ‘D1S’, where: ‘D’ means ‘Discharge’, number (1,2,3,4) is the type and the last letter is used to determine what kind of application the bulb is meant to be.

Will D1S fit D3S?

The metal box is an ‘igniter’ which is generally built as a seperate piece in D2 and D4 systems. Because of these differences, D1 and D3 bulbs cannot be interchanged UNLESS their ballasts are replaced with the corresponding bulbs (you cannot mix components from 2 systems together).

Which way do you install HID bulbs?

Facing up is the correct way.