A/C Fan No. 3 Relay

The A/C fan no. 3 relay, when energized, completes a series circuit from the ALT fuse through the main and auxiliary fan motors. With all three relays energized, voltage is applied through the auxiliary fan motor, through the A/C fan no. 2 relay, through the A/C fan no. 3 relay, and through the main fan motor to ground. Under these conditions, the series circuit is complete and the motors both run at half-speed. If high engine coolant temperature or high refrigerant pressure causes one or more of the relays to de-energize, the main and auxiliary fan motor circuit is switched from series to parallel configuration. In the parallel circuit, the auxiliary fan motor is provided a direct ground (instead of grounding through the main fan motor) and runs at full speed and the main fan motor is provided a direct power feed (instead of through the auxiliary fan motor) and runs at full speed.