I have an older model mastercool so old in fact the serial number and model numbers have long since faded... It only has 4 wires that come out to wire up to the thermastat. Red, Yellow, Green and White. The problem is I can't figure on which is Power, Fan, Pump and whatever....? is there anything that can be done short of calling out the repair guy?

Heating & Cooling - Mastercool - 67680 Evaporative Cooler Air Conditioner