The HVAC control module receives a position signal from the air temperature
actuator. The air temperature actuator position sensor is a potentiometer that is
tied up to a 5-volt reference source. The variable output from the potentiometer feeds
back a position signal to a pull-up resistor which is located in the HVAC control
module. This signal determines the necessary drive signal to the actuator motor, which
provides the proper air temperature door position. This value is stored in the KEEP
ALIVE memory portion of the HVAC control module.
DTC Parameters
| • | The ignition is in the RUN position. |
| • | RED circuit 130 shorted to ground, voltage or open |
| • | WHT circuit 733 shorted to voltage ground or open |
| • | Open grounds circuit 550 BLK/WHT |
Diagnostic Aids
| • | If the DTC is in history or an intermittent condition, perform the test
shown by wiggling wiring and connectors. This will cause malfunction to appear. |
| • | Visually inspect sensor connector and harness for damage, corrosion or
water intrusion. |
| • | Inspect connector halves for poor mating or terminal not fully seated
in the connector body (backed out). |
| • | Inspect for adequate terminal tension, mis-routed harness, rubbed-through
wire insulation and broken wire inside the insulation. |
| • | Inspect for improperly formed or damaged terminals. All connector terminals
in the related circuit should be carefully reformed or replaced to ensure proper contact
tension. |
