Operation CHARM: Car repair manuals for everyone.

Amplifier

Amplifier

Main Blower Relay:





Function: Automatic temperature control is achieved by comparing the in-car temperature at the sensor with that set at the manual temperature selector. Any difference in these two settings causes an IMBALANCE voltage situation in the amplifier which in turn signals the servo control motor through a relay to rotate the camshaft to either the heating or cooling mode.


When the camshaft rotates, a feedback potentiometer also rotates and as the system starts to heat or cool the interior, the feedback potentiometer commences to return the camshaft back to the balance position. Any sudden change in ambient temperature is sensed by the ambient sensor and through the in-car sensor can modify the camshaft position calling for more heating or cooling before the in-car sensor could reflect the ambient change itself.