Abstract: An air temperature control assembly has an air temperature control unit with an optical receiver. A cover houses the air temperature control unit and the optical receiver. A light guide reflects light signals to the optical receiver. The light guide may be a reflecting surface angled to direct the light signal to the optical receiver.

Abstract: A device for monitoring the state of relay contacts is especially useful for controlling motor windings in air conditioning systems. When a first relay switch, which is operative to supply power to a first motor winding does not open as desired, a switch monitoring module responsively controls the second relay switch energization to prevent the second relay switch from being closed. This prevents power that would be supplied to a second motor winding from being also supplied to the first motor winding and causing potential damage to the first motor winding. A disclosed example includes an opto isolator that is energized only when the first relay switch is open as desired. The opto isolator controls an output signal to a second relay control portion, which only operates the second relay if the first relay has opened as required.

Abstract: A device for monitoring the state of relay contacts is especially useful for controlling motor windings in air conditioning systems. When a first relay switch, which is operative to supply power to a first motor winding does not open as desired, a switch monitoring module responsively controls the second relay switch energization to prevent the second relay switch from being closed. This prevents power that would be supplied to a second motor winding from being also supplied to the first motor winding and causing potential damage to the first motor winding. A disclosed example includes an opto isolator that is energized only when the first relay switch is open as desired. The opto isolator controls an output signal to a second relay control portion, which only operates the second relay if the first relay has opened as required.