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 Electrical Diagrams.
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
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 (Continuous Memory Diagnostic Trouble Codes). REPEAT the self-test.
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 (Continuous Memory Diagnostic Trouble Codes). REPEAT the self-test. TEST the system for normal operation.
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. 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.