Pinpoint Test P: All HVAC Functions Inoperative

Climate Control System

Pinpoint Test P: All HVAC Functions Inoperative

Refer to Wiring Diagram Set 54, Manual Climate Control System for schematic and connector information. Diagrams By Number

Normal Operation

The HVAC module receives a ground. The HVAC module is supplied constant battery voltage and ignition voltage.

This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- HVAC module
- Battery
- Charging system concern

PINPOINT TEST P: ALL HVAC FUNCTIONS INOPERATIVE

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P1 CHECK THE HVAC MODULE VOLTAGE SUPPLY CIRCUITS FOR AN OPEN

- Ignition OFF.
- Disconnect: HVAC Module C228A.
- Ignition ON.
- With the engine running, measure the voltage between ground and:
- HVAC module C228A-10, circuit SBP07 (WH/RD), harness side.
- HVAC module C228A-14, circuit CBP21 (BU/GY), harness side.




- Are the voltages greater than 10 volts?

Yes
GO to P2.

No
REPAIR circuit SBP07 (WH/RD) or CBP21 (BU/GY) for high resistance. CLEAR all CMDTCs. REPEAT the self-test.

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P2 CHECK THE HVAC MODULE GROUND CIRCUIT FOR AN OPEN

- Ignition OFF.
- Measure the resistance between ground and HVAC module C228A-13, circuit GD115 (BK/GY), harness side.




- Is the resistance less than 5 ohms?

Yes
GO to P3.

No
REPAIR circuit GD115 (BK/GY) for high resistance. CLEAR all CMDTCs. REPEAT the self-test. TEST the system for normal operation.

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P3 CHECK THE HVAC MODULE CONNECTION

- Disconnect all the HVAC module connectors.
- Inspect the HVAC module connectors for:

- corrosion.
- pushed-out terminals.
- damaged terminals.
- Connect and correctly seat all the HVAC module connectors.
- Operate the system and verify the concern is still present.
- Is the concern still present?

Yes
INSTALL a new HVAC module. REFER to Climate Control Heating Ventilation Air Conditioning (HVAC) Module. TEST the system for normal operation.

No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. TEST the system for normal operation.

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