Originally Posted by gooch
sounds like the switch that you can access is a dead end three way. typically three way systems are powered at on end, and the switch leg is on the other end with 2 traveller wires inbetween. in a dead end 3way its powered and switched from one side and the power is attached to the intended nuetral wire of your traveller wire so that it acts as the power on the other end. the switch its self doenst need a neutral so there is no neutral in that dead end side. the easiest way to do it is bring wire for your new light straight out of your existing light. if you cant do that then you will have to get your wire into that box with the power and the switchleg. if you could somehow access the switchleg to the light you could cut it and j-box it to your new light.
no, no. no!
don't mess with switchlegs ...
either your feed is at the light or one of the switches.
In either case, the simplest way to add a light is at the first light. You KNOW the neutral and switched wire are there....