A4 headlight bulbs

[Cody Forbes]

> Q2. (I feel like such a newb...) Since the A4 bulbs are problematic to get
> to, is there an easy way to tell what you have (halogen vs. HID), short of
> removing the headlamp assembly to get to the bulbs?
>
> ********HID are easy to identify : they start slowly (rather like a
> fluorescent tube in your office), and then get brighter after 2 or 3
> seconds. Halogens are 100% in the first second. More, usually, there is 
> two
> telltale : first is the fact that the HID lens must be plastic, second is
> the presence of an automatic leveling system that works on each start-up.
> The latter is not mandatory anymore on newer cars, for a reason that I 
> don't
> know. I've seen recent Miatas and Jettas with HID and no leveling systems
> but still plastic lenses.

Also HID's are nearly always a fairly blue or at least vivid bright white to 
blue-white color of light while halogens are yellow or at best a yellowish 
off-white. Most HID's when starting will flash super bright light a photo 
camera flash bulb, then instantly dim to almost off and over a second or so 
will level off to normal brightness. When looking at the light pattern HID's 
will have a very very sharp cut-off point at the top (aim at a wall for the 
easiest view), a laser straight line (one side might have a stair step in it 
to put more light on the trees) with the transition from full brightness to 
zero light in an inch or two, basically no shaddowy area.

-Cody