How does a stock temp gauge work?

[Tomsriv]

I looked at the wiring diagrams and they are all for idiot light trucks. I have a pink wire and a green wire coming off the gauge cluster I am swapping into my truck. My truck is missing the original wiring for the sender, so I can't go by whats there.
I assume one wire takes power from the dash and the other wire goes to the sender. Can someone with a stock gauge setup tell me what color the wire is to the sender?

Thanks