Temperature Control

The Water Shut-Off Solenoid controls the flow of engine coolant through the heater core. When the Solenoid is energized, coolant flow is shut off to allow maximum cooling from the Air Conditioning System. The Water Shut-Off Solenoid is controlled by the Hot Water Cut-Off Switch, that is part of the A/C Control Panel Temperature Control.

Battery voltage is applied through Fuse 20 to the Hot Water Cut-Off Switch when the ignition Switch is in the RUN position. The Hot Water Cut-Off Switch is closed when the TEMP Control is rotated fully counterclockwise (coldest position), and opens when the Control is rotated more than 20 degrees in a clockwise direction. When the Switch is closed, battery voltage is applied through the A/C In-Line Fuse to the Water Shut-Off Solenoid. The Solenoid is energized and shuts off the coolant flow through the heater core.

The Water Shut-Off Solenoid and A/C In-Line Diode are protected by the A/C In-Line Fuse. If any failures occur in the Solenoid or Diode, the Fuse will isolate them to prevent the failure from affecting other parts of the Heating and Air Conditioning Circuits.