Aaron Fude wrote:
I would guess they need three: one for cooling part, one for the fan,
and one neutral.

So why 5?

Thanks!

Years ago I learned the following:
Red = Hot = Power (24 volt) = R terminal
Green = Go = Blower = G terminal
White = Snow = Heat = W terminal
Yellow = Sun = A/C = Y terminal
Blue = Cool = A/C (If there is no Yellow wire) = Y terminal
The 5th wire = Common = C terminal

--
Moe Jones
http://www.MoeJones.info