HID converstion. All the kits I see require an additional power lead. Why?

An HID ballast needs 35 watts and a stock headlight uses 55 watts. Why can't you use the stock headlight wiring to power the ballast and add a 20 watt resistor to match the 55 watt draw?

With a 55 watt draw the SJB will be happy, and it would save hacking up the stock wiring.

I know the resistor will generate some heat, but is it enough to be an issue.

 

Because the stock lamp is a pure resistive load. The ballast looks NOTHING like a resistive load to the SJB. In fact, its so different that it drives the SJB nuts and the headlamps do not function correctly.

There is no 'hacking' of the wiring harness to install correctly, a preinstalled ring terminal bolts to the SJB input lug. Ground bolts to an existing vehicle ground just forward of the shock tower.