Attach the ground and white wires to the bus bar located at the back of the panel box. Is there a final diagram of how you got it to work if so. This is the hot wire Black coming from a breaker. Take the Romex cable and guide it from the electric makeup box of the swamp cooler to the electric panel box with the breakers. If you look at the upper right corner of the drawing, you'll notice that it already said that. The Packard delay relay does not need a neutral, from what I can tell.
The standard method is to use a SPDT contact to change speeds so that voltage is only applied to either the Low or the High but never both.
Evaporative Swamp Cooler Switch Thermostat Wiring
Also UP-Dux "are much less effective" is not my experience at all. My swamp cooler only runs the pump on low cool. Dale Coffing Dale Coffing 21 2. A blower motor blows air into a building and can be either volts AC, or volts AC, and will also have connections for low and high speeds.