SHAFT A 0620840 - Caterpillar

Illustration 1 g00292331
An amplifier that is controlled by a microcomputer sends a signal to the DC motor of the air inlet temperature switch (Face and Foot). When the DC motor is activated, the damper position shifts from FACE to FOOT or from FOOT to FACE. The potentiometer detects the damper position. The potentiometer then sends a signal back to the amplifier.
Illustration 2 g00292318
(x) Angle of potentiometer (°C). (y) Resistance ("KOhms"). (z) ("d" - "e").
Table 1
Terminal    Direction of shift in damper    
"a"    "c"    
-     +     FOOT to FACE    
+     -     FACE to FOOT