2000 Chevy Impala Climate control selection Inoperative

First, make sure the knob isn't broken where it goes on the control shaft. If it's ok, you probably have a bad mode actuator.

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Service Information
2000 Chevrolet Impala | Impala, Monte Carlo (VIN W) Service Manual | HVAC | HVAC Systems - Manual | Diagnostic Information and Procedures | Document ID: 516403

Air Delivery Improper
Important: To avoid misdiagnosis, complete Symptoms before beginning vacuum diagnosis.

This air delivery system uses a manual selector located in the heater-A/C control module to operate vacuum controls in the air distribution ducts.

Check the vacuum supply to the vacuum selector (purple and black vacuum hoses) while the engine is running.
"Â Vacuum should be approximately 40 kPa (6 psi) with engine running.

"Â Vacuum should remain at approximately 40 kPa (6 psi) when engine is turned OFF.

Test each vacuum actuator by disconnecting the vacuum hose and applying vacuum directly to the actuator. Repair or replace as necessary.
Reconnect all vacuum and electrical connections. Start the engine and cycle through the operating modes of the heater-A/C control while observing the valve actuators.
"Â Check for vacuum to the mode valve actuators by noting the mode valve actuator position. When vacuum is applied, the actuator will retract, refer to the Air Delivery Vacuum Distribution table.

"Â If a vacuum actuator retracts when it should not, replace the heater-A/C control module assembly. Refer to Control Assembly Replacement.

"Â If a vacuum actuator does not retract when it should, check for vacuum leaks, collapsed vacuum hoses or binding valves. If these are OK, replace the affected vacuum actuator.

Vacuum Distribution Mode
Vacuum Ports/Vacuum Hose Color/Vacuum Actuator Valve
Abnormal Condition

Defrost

(YEL)

Defrost Valve
Heater

(RED)

Mode Valve
A/C

(BLU)

IP Outlet Valve
Bi-Level

(BRN)

IP Outlet Valve
Air Recirc

(ORN)

Air Inlet Valve

Recirculation
Vent
Vacuum
Vacuum
Vent
Vacuum
Refer to Air Inlet Actuator Replacement or Air Inlet Valve Replacement in Heating, Ventilation and Air Conditioning

Bi-Level
Vent
Vacuum
Vent
Vent
Vent
Refer to Mode Actuator Replacement or Mode Valve Replacement or Air Inlet Valve Replacement in Heating, Ventilation and Air Conditioning

Upper
Vent
Vacuum
Vacuum
Vent
Vent
Refer to Mode Actuator Replacement or Defroster Valve Replacement in Heating, Ventilation and Air Conditioning

Lower
Vent
Vacuum
Vent
Vacuum
Vacuum
Refer to Mode Actuator Replacement or Mode Valve Replacement in Heating, Ventilation and Air Conditioning

Defog
Vent
Vent
Vent
Vacuum
Vent
Refer to Defroster Valve Actuator Replacement or Defroster Valve Replacement in Heating, Ventilation and Air Conditioning

Defrost
Vacuum
Vent
Vent
Vacuum
Vent
Refer to Defroster Valve Actuator Replacement or Defroster Valve Replacement in Heating, Ventilation and Air Conditioning

Outside Air
Vent
Vacuum
Vent
Vent
Vacuum
Refer to Air Inlet Actuator Replacement or Mode Valve Replacement in Heating, Ventilation and Air Conditioning

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