What are "Bi-xenon" projectors?

These projectors use solenoids to change the position of the metal shield that creates the cut off line, so that in one position "up" it acts as a cutoff to prevent light from blinding oncoming drivers, and in the other position "down" this restriction is removed for full brightness. The problem is that there are actually two solenoids in this package, one for pulling and one for holding, and consequently there is a 3-wire connector on the projector. For proper operation, the pull coil is supposed to be activated for about 1/10 - 1/5 of a second, and then turned off while the hold coil is still powered as long as high beams are desired. The hold coil alone is not strong enough to move the shield, only to hold it in the high- beam position. FX projectors on the other hand do not require a 3-wire set up, but rather just two wires that allow a much easier set up as well as install. Below are a couple of videos of a dual FX35 bi-xenon projector set up for an '07 Jeep Grand Cherokee: [- ...  more