A switch to turn all aux lights on

Do I run a red wire from all the lights to one relay and a switch?

Also, how do you wire two switches that control the same lights? Split the red wire from the device to two different relays?

 

It depends on the "total" current of all the lights combined. As long as the wire size, fuse size and relay size will hold the total current - your good.

Not quite sure where your headed here? You want the lites to come on with aftermarket dash switch? And also triggered by an OE switch too? If so, I strongly suggest two relays.

This is a drawing I made for something else. But the principal is the same.