Single Speed Fan (Without A/C)

Voltage is present at the Ignition Relay contacts at all times through the COOLING FAN Fuse Link Cartridge. The Ignition Relay coil is grounded through the Starter Assembly.

With the Ignition Switch in START or RUN, voltage is present at the coils of the Ignition Relay, the Cooling Fan Lo Speed Relay and the Cooling Fan Hi Speed Relay. The Ignition Relay coil is energized and the contacts close. Voltage is now present at the contacts of the Cooling Fan Lo Speed Relay and the Cooling Fan Hi Speed Relay.

With engine coolant temperature below 220 degrees F, the Electronic Engine Control (EEC) Module immediately grounds pin 35 and the Cooling Fan Lo Speed Relay coil. The Relay energizes and the contacts open; the Electric Cooling Fan does not run.

If engine coolant temperature reaches 220 degrees F, the (EEC) Module ungrounds pin 35 and the Cooling Fan Lo Speed Relay coil. The Relay deenergizes and the contacts close. Current flows through the COOLING FAN Fuse Link Cartridge, the Ignition Relay, circuit 727, the Cooling Fan Hi Speed Relay (deenergized), circuit 729, the Cooling Fan Lo Speed Relay (deenergized) and the Electric Coling Fan to ground; the Electric Cooling Fan runs.

If coolant temperature drops to 212 degrees F, the EEC Module again grounds pin 35 and energizes the Cooling Fan Lo Speed Relay; the Electric Cooling Fan stops running

If coolant temperature continues to rise and reaches 230 degrees F, the EEC Module grounds pin 31 and the Cooling Fan Hi Speed Relay coil. The coil energizes and the contacts close. Current flows through the COOLING FAN Fuse Link Cartridge, the Ignition Relay, the Cooling Fan Hi Speed Relay, circuit 728, and the Electric Cooling Fan to ground; the Electric Cooling Fan runs.