there are 3 wires coming off from the 2001+ rectangular ballast. what is the 3rd wire do? I know probably 2 of them are regarding Pos+ and Neg- but what does the 3rd wire do?

 

Bump.... Good question.

 

hrm...

good question. my guess would be that 1 is positive power, 1 is ground, and 1 is a switching power (tells the lights to turn on and draw power from the main power). that way, you don't have to rate your power switch for full draw on the headlight.

completely guess - very possibly wrong - as i'd guess a relay elsewhere would perform the switching function... but i can't think of anything better at the moment.

 

interesting, is that why HID's use less power afterwards? because it draws on a different circuit after the ARC has been ignited?

 

it was just a guess.....


actually, no - i think that's a function of the HID design. you need a lot of voltage to get the arc initiated, and less to maintain.