Wiring a switch, power from outlet
I'm confused over some wiring, and I hope you can help.
I'm trying to reinstall a switch that powers an inside outlet, but it is feed from the same outlet it's powering. This outlet is feed from a GFCI outlet in another room.
I have three wires at the switch, Red, Black, and White.
There is another switch (a timer) in this double box for outside lights that I just installed. I ran feed and load (12/2) wires to this timer, off of a dedicated GFCI breaker.
Both GFCI breakers trip, if I hook up the white wire from the outlet to the neutrals of the new circuit. If I leave that white wire off, then the outside lights work fine.
I looked at the outlet that feeds the switch, and there are two white wires on the neutral of the outlet, and the Red one is on the other side of the outlet.
My question is which wires hook to the switch?
Can the black, from the outlet to the switch, be put in with the neutrals of the new circuit? There's only two screws on the switch, and I'm pretty sure the red has to go to one, so it's the black and white I'm confused about.
Thanks for any help,