Originally Posted by cadillackid
there are different LED replacement bulbs sold.. a buddy of mine and I found that some unfortunately did a terrible job of dim and bright.. where the bright function was almost indifferent than the dim.. it took buying higher quality bulbs to get a good differential.. like CREE ..
if you swapped the whole 7 inch and 4 inch fixtures out for LED.. then typically the black wire is low (dim) and the red wire is High (bright).. and ground is achieve through the caseing of the fixture and screws into the bus body..
Yup, which is typically two lines. But as you said some LED's are On or OFF, not any brighter or dimmer, digital per se. Not analogue like incandescent bulbs which brighten and dim based on voltage received. Dimmer LED's are designed with multiple diodes, or designed with better more costly diodes that can operate a different voltages to present the dimming effect but even those aren't analogue, they are just designed with basically multiple diodes that determine which diode to switch to based on the voltage supplied.