Originally posted by EliteAccord
USC - What does a relay really do? I'm not too familiar with electrical stuff. I know I had a relay with both my 9006 HID and now my E39 HID. Is it like a power regulator?
well, if you get the chance, swing by a local radio smack and look at their relays. usually there's a diagram on them.
a relay functions pretty much like an electrical switch. it allows you to route power from various sources, or to various targets
for example, let's say:
A = source A
B = source B
S = switch
C = target C
say you connect A to nothing, and B to battery, S to the 9006 harness, and C = ballast. right now, the default is A -> C. which means ballast isn't getting any juice from anywhere. but once you turn on your headlights, feeding electricty to S, the relay then swaps sources... instead of A -> C, it's now B -> C. and voila, HID.
that's the jist of it.