Ok I have read through the manual and it is not helpful at all.

The DX3s is a 3 channel radio right? Then why can't I use the 3rd channel for something other than mixing the servos? I just installed a light kit in my SC10 and want to be able to hit a button on the radio and turn them on and off, did I just miss something in the manual? Is this possible with this radio?

curious, how would you tell the lights to turn on and off just by plugging them into the third channel?

From what I can tell there is constant power running through the aux slot on the rx. It has been the slot my transponder was always plugged into. I mainly want to know if it can be linked to a button and be turned off on command?

good question. I would think you could jury rig something with a servo setup of some sort. Have you tried contacting Spektrum? I myself am doing a light setup with a siren combined, it would be cool to be able to do that from the radio.