Power is supplied to both green and blue wires to power the motor. The motor reverses based on which wire gets the positive and negative from the battery through two independent relays. The two relays does the switching depending on the Up and Down T&T switch. No electrical connection to ground. The T&T switch only activates or energized each of the relay at a time. The relay does the connection to the positive battery power depending which relay is energized.
When the system is not energized or activated, both green and blue wires are connected to the negative terminal wires (in each of their own relays. There are 2 separate relays) in the relays' normally close (NC) contacts. When a relay is energized by the switch selector, e.g. in the Up position, the "Up" relay (with blue wire connection) activates disconnecting the blue wire from ground (NC terminal) and connecting it to the positive terminal wire (normally open terminal). Thus the blue wire gets positive connection while the green stays connected to negative terminal wire (in the Down relay), energizing the motor (actually in this configuration the motor turns clockwise).
The same operation when the selector switch is depressed in the Down position, the "Down" relay (with green wire connection) gets energized and activates to disconnect the green wire from the NC (negative wire connection) contact to the positive terminal wire (NO) terminal, while the blue wire stays connected to the negative terminal wire in the Up relay. Thus energizing the motor CCW.
