HVAC - Climate Control System - General Information and Diagnostics: Overview Ford Fiesta Mk6

Climate Control System Operation

Failure to follow these instructions may result in serious personal injury .

Note. To avoid damaging the vehicle or Air Conditioning (A/C) components, observe the following precautions. Identify and analyze the A/C refrigerant of all vehicles prior to refrigerant charging. Failure to do so can contaminate the shop bulk refrigerant and other vehicles. Do not add R-12 refrigerant to an A/C system that requires the use of R-134a refrigerant. These 2 types of refrigerant must never be mixed. Doing so can damage the A/C system. Charge the A/C system with R-134a refrigerant gas while the engine is running only at the low-pressure side to prevent refrigerant slugging from damaging the A/C compressor. Use only R-134a refrigerant. Due to environmental concerns, when the A/C system is drained, collect the refrigerant using refrigerant recovery/recycling equipment. Federal, State/Provincial and/or local laws REQUIRE that R-134a be recovered into appropriate recovery equipment and the process be conducted by qualified technicians who have been certified by an approved organization, such as ASE or Mobile Air Conditioning Society (MACS). Use of a recovery machine dedicated to R-134a is necessary to reduce the possibility of oil and refrigerant incompatibility concerns. Refer to the instructions provided by the equipment manufacturer when removing refrigerant from or charging the A/C system. R-134a Refrigerant must not be mixed with air for leak testing or used with air for any other purpose above atmospheric pressure. R-134a is combustible when mixed with high concentrations of air and higher pressures. A number of manufacturers are producing refrigerant products described as direct substitutes for R-134a. The use of any unauthorized substitute refrigerant can severely damage the A/C components. If repair is required, use only new or recycled R-134a refrigerant.

Note. To avoid contamination of the Air Conditioning (A/C) system, observe the following precautions. Never open or loosen a connection before recovering the refrigerant. When loosening a connection, if any residual pressure is evident, allow it to leak out before opening the fitting. Evacuate a system that has been opened to install a new component or one that has discharged through leakage before charging. Seal open fittings with a cap or plug immediately after disconnecting a component from the system. Clean the outside of the fittings thoroughly before disconnecting a component from the system. Do not remove the sealing caps from a new component until ready to install. Refrigerant oil will absorb moisture from the atmosphere if left uncapped. Do not open an oil container until ready to use and install the cap immediately after using. Store the oil in a clean, moisture-free container. Install a new O-ring seal before connecting an open fitting. Coat the fitting and O-ring seal with PAG oil before connecting. When installing a refrigerant line, avoid sharp bends. Position the line away from the exhaust or any sharp edges that can chafe the line. Tighten threaded fittings only to specifications. The steel and aluminum fittings used in the refrigerant system will not tolerate overtightening. When disconnecting a fitting, use a wrench on both halves of the fitting to prevent twisting of the refrigerant lines or tubes. Do not open a refrigerant system or uncap a new component unless it is as close as possible to room temperature. This will prevent condensation from forming inside a component that is cooler than the surrounding air.

The climate control system, not equipped with A/C , consists of the following components

1. Heater core and evaporator core housing
2. HVAC module
3. Instrument Panel Cluster (IPC)
4. Temperature blend door actuator
5. Floor/defrost/panel mode door actuator
6. Air inlet mode door actuator
7. Blower motor resistor
8. Blower motor

The climate control system, equipped with A/C , consists of the following components

1. A/C compressor
2. A/C compressor clutch assembly
3. A/C condenser core
4. A/C evaporator core
5. Receiver/drier
6. Connecting refrigerant lines
7. Thermostatic Expansion Valve (TXV)
8. Heater core and evaporator core housing
9. HVAC module
10. Instrument Panel Cluster (IPC)
11. Temperature blend door actuator
12. Floor/defrost/panel mode door actuator
13. Air inlet mode door actuator
14. Blower motor resistor
15. Blower motor
16. Evaporator discharge air temperature sensor

HVAC System Operation

The Electronic Manual Temperature Control (EMTC) system heats or cools the vehicle depending on the HVAC control panel selection.

1. The control panel selection determines heating or cooling, air distribution and enables blower motor operation.
2. The temperature control setting determines the air outlet temperature.
3. The blower motor switch varies the blower motor speed.
4. During A/C operation (if equipped), the system reduces the relative humidity of the air inside the vehicle.

Normal Operation

Under normal operation, the A/C pressure transducer receives a ground from the PCM. A 5-volt reference voltage is supplied to the A/C pressure transducer from the PCM. The A/C pressure transducer then sends a voltage to the PCM to indicate the A/C pressure.

1. DTC P0532:16 (A/C Refrigerant Pressure Sensor A Circuit Low: Circuit Voltage Below Threshold) - The A/C pressure transducer inputs a feedback voltage to the PCM. This DTC sets if the feedback voltage is less than 0.26 volts for at least 2 seconds and the ambient air temperature is greater than 0C° (32F°).
2. DTC P0533:17 (A/C Refrigerant Pressure Sensor A Circuit High: Circuit Voltage Above Threshold) - The A/C pressure transducer inputs a feedback voltage to the PCM. This DTC sets if the feedback voltage is greater than 4.95 volts for at least 2 seconds and the ambient air temperature is greater than 0C° (32F°). This pinpoint test is intended to diagnose the following
3. Wiring, terminals or connectors
4. A/C pressure transducer
5. PCM

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1. A1 CHECK THE PCM OUTPUT VOLTAGE Ignition OFF. Disconnect: A/C Pressure Transducer C1260. Ignition ON. Measure the voltage between ground and A/C pressure transducer C1260-2, circuit LH108 (GY/BN), harness side. Is the voltage between 4.7 and 5.1 volts? Yes: Go to A4 . No: If the voltage is less than 4.7 volts, go to A2 . If the voltage is greater than 5.1 volts REPAIR circuit LH108 (GY/BN) for a short to voltage. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
2. A2 CHECK THE REFERENCE VOLTAGE CIRCUIT FOR A SHORT TO GROUND Ignition OFF. Disconnect: PCM C175B. Measure the resistance between ground and A/C pressure transducer C1260-2, circuit LH108 (GY/BN), harness side. Is the resistance greater than 10,000 ohms? Yes: Go to A3 . No: REPAIR circuit LH108 (GY/BN) for a short to ground. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
3. A3 CHECK THE REFERENCE VOLTAGE CIRCUIT FOR AN OPEN Measure the resistance between A/C pressure transducer C1260-2, circuit LH108 (GY/BN), harness side and PCM C175B-16, circuit LH108 (GY/BN), harness side. Is the resistance less than 5 ohms? Yes: Go to A15 . No: REPAIR circuit LH108 (GY/BN) for an open. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
4. A4 CHECK THE PCM SENSOR GROUND Measure the voltage between A/C pressure transducer C1260-1, circuit RH108 (BN), harness side and A/C pressure transducer C1260-2, circuit LH108 (GY/BN), harness side. Is the voltage greater than 4.7 volts? Yes: If diagnosing DTC P0532 , Go to A8 . If diagnosing DTC P0533 , go to A11 . No: Go to A5 .
5. A5 CHECK THE SIGNAL RETURN CIRCUIT FOR VOLTAGE Ignition OFF. Disconnect: PCM C175B. Ignition ON. Measure the voltage between ground and A/C pressure transducer C1260-1, circuit RH108 (BN), harness side. Is any voltage present? Yes: REPAIR circuit RH108 (BN) for a short to voltage. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation. No: Go to A6 .
6. A6 CHECK THE SIGNAL RETURN CIRCUIT FOR A SHORT TO THE REFERENCE VOLTAGE CIRCUIT Measure the resistance between A/C pressure transducer C1260-1, circuit RH108 (BN), harness side and A/C pressure transducer C1260-2, circuit LH108 (GY/BN), harness side. Is the resistance greater than 10,000 ohms? Yes: Go to A7 . No: REPAIR circuit RH108 (BN) for a short to circuit LH108 (GY/BN). CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
7. A7 CHECK THE SIGNAL RETURN CIRCUIT FOR AN OPEN Ignition OFF. Measure the resistance between A/C pressure transducer C1260-1, circuit RH108 (BN), harness side and PCM C175B-40, circuit RH108 (BN), harness side. Is the resistance less than 5 ohms? Yes: Go to A15 . No: REPAIR circuit RH108 (BN) for an open. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
8. A8 CHECK THE A/C PRESSURE TRANSDUCER Enter the following diagnostic mode on the scan tool: PCM DataLogger. Observe the A/C Pressure Sensor (ACP_V) PCM PID voltage. Does the ACP_V PCM PID voltage read greater than 4.7 volts? Yes: INSTALL a new A/C pressure transducer. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation. No: Go to A9 .
9. A9 CHECK THE A/C PRESSURE TRANSDUCER FEEDBACK CIRCUIT FOR A SHORT TO THE SIGNAL RETURN CIRCUIT Ignition OFF. Disconnect: PCM C175B. Measure the resistance between A/C pressure transducer C1260-3, circuit VH442 (GN/BN), harness side and A/C pressure transducer C1260-1, circuit RH108 (BN), harness side. Is the resistance greater than 10,000 ohms? Yes: Go to A10 . No: REPAIR circuit VH442 (GN/BN) for a short to circuit RH108 (BN). CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
10. A10 CHECK THE A/C PRESSURE TRANSDUCER FEEDBACK CIRCUIT FOR A SHORT TO GROUND Measure the resistance between ground and A/C pressure transducer C1260-3, circuit VH442 (GN/BN), harness side. Is the resistance greater than 10,000 ohms? Yes: Go to A15 . No: REPAIR circuit VH442 (GN/BN) for a short to ground. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
11. A11 CHECK THE A/C PRESSURE TRANSDUCER FEEDBACK CIRCUIT FOR A SHORT TO VOLTAGE Ignition OFF. Disconnect: PCM C175B. Ignition ON. Measure the voltage between ground and A/C pressure transducer C1260-3, circuit VH442 (GN/BN), harness side. Is any voltage present? Yes: REPAIR circuit VH442 (GN/BN) for a short to voltage. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation. No: Go to A12 .
12. A12 CHECK THE A/C PRESSURE TRANSDUCER FEEDBACK CIRCUIT FOR A SHORT THE REFERENCE VOLTAGE CIRCUIT Measure the resistance between A/C pressure transducer C1260-3, circuit VH442 (GN/BN), harness side and A/C pressure transducer C1260-2, circuit LH108 (GY/BN), harness side. Is the resistance greater than 10,000 ohms? Yes: Go to A13 . No: REPAIR circuit VH442 (GN/BN) for a short to circuit LH108 (GY/BN). CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
13. A13 CHECK THE A/C PRESSURE TRANSDUCER FEEDBACK CIRCUIT FOR AN OPEN Measure the resistance between A/C pressure transducer C1260-3, circuit VH442 (GN/BN), harness side and PCM C175B-28, circuit VH442 (GN/BN), harness side. Is the resistance less than 5 ohms? Yes: Go to A14 . No: REPAIR circuit VH442 (GN/BN) for an open. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
14. A14 CHECK THE A/C PRESSURE SENSOR (ACP_V) PCM PID WITH THE A/C PRESSURE TRANSDUCER SHORTED NOTE: If the jumper fuse opens while carrying out this test step, repair circuit VH442 (GN/BN) for a short to ground. Ignition OFF. Connect: PCM C175B. Ignition ON. Enter the following diagnostic mode on the scan tool: PCM DataLogger. While observing the ACP_V PCM PID, connect a fused jumper between A/C pressure transducer C1260-1, circuit RH108 (BN), harness side and A/C pressure transducer C1260-3, circuit VH442 (GN/BN), harness side. Does the ACP_V PCM PID voltage read 0 volts? Yes: INSTALL a new A/C pressure transducer. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation. No: Go to A15 .
15. A15 CHECK THE PCM CONNECTION Disconnect all the PCM connectors. Inspect the PCM connectors for: corrosion. pushed-out terminals. damaged terminals. Connect and correctly seat all the PCM connectors. Operate the system and verify the concern is still present. Is the concern still present? Yes: INSTALL a new PCM. Refer to «ELECTRONIC ENGINE CONTROLS»(ref-382403) . 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.

Voltage is provided to the A/C clutch relay coil. When A/C is requested and A/C line pressures allow, a ground is provided to the A/C clutch relay coil from the PCM, energizing the A/C clutch relay.

1. DTC P0645:13 (A/C Clutch Relay Control Circuit: Circuit Open) - This DTC sets when the relay circuit is OFF and no voltage is detected on the relay circuit. The PCM expects to detect voltage coming through the relay coil to the relay circuit when it is not grounding it.
2. DTC P0646:11 (A/C Clutch Relay Control Circuit Low: Circuit Short To Ground) - This DTC sets when the relay circuit is OFF and ground is detected on the relay circuit. The PCM expects to detect voltage coming through the relay coil to the relay circuit when it is not grounding it.
3. DTC P0647:12 (A/C Clutch Relay Control Circuit High: Circuit Short To Battery) - This DTC sets when the PCM grounds the relay circuit and excessive current draw (short to voltage) is detected on the relay circuit. This pinpoint test is intended to diagnose the following
4. Wiring, terminals or connectors
5. A/C clutch relay
6. PCM

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1. B1 CHECK PCM DTCS Ignition ON. Check the PCM DTCs retrieved during the self-test. Is DTC P0645:13 present? Yes: Go to B2 . No For DTC P0646:11 , go to B5 . For DTC P0647:12 , go to B6 .
2. B2 CHECK THE VOLTAGE TO THE A/C CLUTCH RELAY COIL Ignition OFF. Disconnect: A/C Clutch Relay. Ignition ON. Measure the voltage between ground and the A/C clutch relay socket pin 1, circuit CBP02 (GN). Is the voltage greater than 10 volts? Yes: Go to B3 . No: VERIFY Central Junction Box (CJB) fuse 2 (10A) is OK. If OK, REPAIR circuit CBP02 (GN) for an open. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation. If not OK, Refer to the appropriate SYSTEM WIRING DIAGRAMS article to identify the possible causes of the circuit short.
3. B3 CHECK THE A/C CLUTCH RELAY NOTE: The following step uses a test light to simulate normal circuit loads. Use only the test light recommended in the Special Tools table at the beginning of this information or equivalent. To avoid connector terminal damage, use the Flex Probe Kit for the test light probe connection to the vehicle. Do not use the test light probe directly on any connector. Start the engine. Select PANEL and press the A/C button (indicator on) on the HVAC controls. With the engine running, connect a 12-volt test light between A/C clutch relay socket pin 1, circuit CBP02 (GN) and A/C clutch relay socket pin 2, circuit CH302 (WH/BN). Does the test light illuminate? Yes: INSTALL a new A/C clutch relay. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation. No: Go to B4 .
4. B4 CHECK THE A/C CLUTCH RELAY COIL SWITCHED GROUND CIRCUIT FOR AN OPEN Ignition OFF. Disconnect: PCM C175B. Measure the resistance between A/C clutch relay socket pin 2, circuit CH302 (WH/BN) and PCM C175B-25, circuit CH302 (WH/BN), harness side. Is the resistance less than 5 ohms? Yes: Go to B7 . No: REPAIR circuit CH302 (WH/BN) for an open. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
5. B5 CHECK THE A/C CLUTCH RELAY COIL SWITCHED GROUND CIRCUIT FOR A SHORT TO GROUND Ignition OFF. Disconnect: A/C Clutch Relay. Disconnect: PCM C175B. Measure the resistance between ground and PCM C175B-25, circuit CH302 (WH/BN), harness side. Is the resistance greater than 10,000 ohms? Yes: Go to B7 . No: REPAIR circuit CH302 (WH/BN) for a short to ground. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
6. B6 CHECK THE A/C CLUTCH RELAY COIL SWITCHED GROUND CIRCUIT FOR A SHORT TO VOLTAGE Ignition OFF. Disconnect: A/C Clutch Relay. Disconnect: PCM C175B. Ignition ON. Measure the voltage between ground and PCM C175B-25, circuit CH302 (WH/BN), harness side. Is any voltage present? Yes: REPAIR circuit CH302 (WH/BN) for a short to voltage. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation. No: Carry out the A/C clutch relay component test. Refer to appropriate SYSTEM WIRING DIAGRAMS article for component testing. If the relay tests OK, go to B7 .
7. B7 CHECK THE PCM CONNECTION Disconnect all the PCM connectors. Inspect the PCM connectors for: corrosion. pushed-out terminals. damaged terminals. Connect and correctly seat all the PCM connectors. Operate the system and verify the concern is still present. Is the concern still present? Yes: INSTALL a new PCM. Refer to «ELECTRONIC ENGINE CONTROLS»(ref-382403) . 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.

The evaporator discharge air temperature sensor receives a ground from the Instrument Panel Cluster (IPC). The sensor varies its resistance with the temperature. As the temperature rises, the resistance falls. As the temperature falls, the resistance rises. The IPC measures this resistance on the feedback circuit to determine the temperature at the sensor. The sensor value is sent from the IPC to the PCM through the High Speed Controller Area Network (HS-CAN).

The evaporator discharge air temperature sensor is used for A/C compressor cycling. An accurate evaporator discharge air temperature is critical to prevent evaporator icing. The PCM uses the temperature measurement to turn off the A/C compressor before the evaporator temperature is cold enough to freeze the condensation. This prevents ice blockage of airflow over the evaporator core.

1. DTC B1B71:11 (Evaporator Discharge Air Temperature Sensor: Circuit Short to Ground) - The module senses lower than expected voltage on the sensor feedback circuit, indicating a short to ground.
2. DTC B1B71:13 (Evaporator Discharge Air Temperature Sensor: Circuit Open) - The module senses greater than expected voltage on the sensor feedback circuit, indicating an open circuit or sensor. This pinpoint test is intended to diagnose the following
3. Wiring, terminals or connectors
4. Evaporator discharge air temperature sensor
5. IPC

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1. C1 CHECK THE SENSOR RESISTANCE Ignition OFF. Disconnect: Evaporator Discharge Air Temperature Sensor C296. Allow enough time for the evaporator to stabilize to the ambient temperature. Measure the resistance between evaporator discharge air temperature sensor C296 terminals and compare to the table below. TERMINAL RESISTANCE REFERENCE Ambient Temperature Resistance 0-10C° (32-50F°) 5,892-9,893 ohms 10-20C° (50-68F°) 3,689-6,048 ohms 20-25C° (68-77F°) 2,950-3,805 ohms 25-30C° (77-86F°) 2,374-3,050 ohms 30-35C° (86-95F°) 1,923-2,460 ohms 35-40C° (95-104F°) 1,566-1,996 ohms 40-50C° (104-122F°) 1,057-1,630 ohms Is the resistance within the specified values for the temperatures? Yes: Go to C2 . No: INSTALL a new evaporator discharge air temperature sensor. Refer to «CLIMATE CONTROL»(ref-382426) . CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
2. C2 CHECK THE IPC SENSOR OUTPUT VOLTAGE Ignition ON. Select PANEL and press the A/C button (indicator on) on the HVAC controls. Measure the voltage between evaporator discharge air temperature sensor C296-1, circuit VH406 (VT/BN), harness side and C296-3, circuit RH119 (YE/VT), harness side. Is the voltage between 4.7 and 5.1 volts? Yes: INSTALL a new evaporator discharge air temperature sensor. Refer to «CLIMATE CONTROL»(ref-382426) . CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation. If the DTC returns, go to C7 . No If diagnosing DTC B1B71:13 , go to C3 . If diagnosing DTC B1B71:11 , go to C5 .
3. C3 CHECK THE EVAPORATOR TEMPERATURE SENSOR FEEDBACK CIRCUIT FOR AN OPEN Ignition OFF. Disconnect: Instrument Panel Cluster (IPC) C220. Measure the resistance between IPCC220-26, circuit VH406 (VT/BN), harness side and evaporator discharge air temperature sensor C296-1, circuit VH406 (VT/BN), harness side. Is the resistance less than 5 ohms? Yes: Go to C4 . No: REPAIR circuit VH406 (VT/BN) for an open. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
4. C4 CHECK THE SIGNAL RETURN CIRCUIT FOR AN OPEN Measure the resistance between IPCC220-24, circuit RH119 (YE/VT), harness side and evaporator discharge air temperature sensor C296-3, circuit RH119 (YE/VT), harness side. Is the resistance less than 5 ohms? Yes: Go to C7 . No: REPAIR circuit RH119 (YE/VT) for an open. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
5. C5 CHECK THE EVAPORATOR TEMPERATURE SENSOR FEEDBACK CIRCUIT FOR A SHORT TO THE SIGNAL RETURN CIRCUIT Ignition OFF. Disconnect: IPC C220. Measure the resistance between evaporator discharge air temperature sensor C296-1, circuit VH406 (VT/BN), harness side and C296-3, circuit RH119 (YE/VT), harness side. Is the resistance greater than 10,000 ohms? Yes: Go to C6 . No: REPAIR circuits VH406 (VT/BN) and RH119 (YE/VT) for a short together. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
6. C6 CHECK THE EVAPORATOR TEMPERATURE SENSOR FEEDBACK CIRCUIT FOR A SHORT TO GROUND Measure the resistance between IPCC220-26, circuit VH406 (VT/BN), harness side and ground. Is the resistance greater than 10,000 ohms? Yes: Go to C7 . No: REPAIR circuit VH406 (VT/BN) for a short to ground. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
7. C7 CHECK THE IPC CONNECTION Disconnect all the IPC connectors. Inspect the IPC connectors for: corrosion. pushed-out terminals. damaged terminals. Connect and correctly seat all the IPC connectors. Operate the system and verify the concern is still present. Is the concern still present? Yes: INSTALL a new IPC . Refer to «INSTRUMENTATION, MESSAGE CENTER, AND WARNING CHIMES»(ref-382387) . 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.

A 5-volt reference voltage is supplied to the sensors and actuators from the HVAC module.

1. DTC 4-4 (Feedback Reference Circuit/Performance) - The module senses less than expected voltage on the reference voltage circuit, indicating a short directly to ground or the module senses greater than expected voltage on the sensor reference voltage circuit, indicating an open or a short directly to voltage. This pinpoint test is intended to diagnose the following
2. Wiring, terminals or connectors
3. HVAC module

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1. D1 CHECK THE REFERENCE VOLTAGE CIRCUIT FOR A SHORT TO GROUND Ignition OFF. Disconnect: HVAC Module C228A. Measure the resistance between ground and HVAC module C228A-12, circuit CH232 (WH/BN), harness side. Is the resistance greater than 10,000 ohms? Yes: Go to D2 . No: REPAIR circuit CH232 (WH/BN) for a short to ground. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
2. D2 CHECK THE REFERENCE VOLTAGE CIRCUIT AND THE SIGNAL RETURN CIRCUIT FOR A SHORT TOGETHER Measure the resistance between HVAC module C228A-12, circuit CH232 (WH/BN), harness side and HVAC module C228A-2, circuit CH233 (VT/BN), harness side. Is the resistance greater than 100 ohms? Yes: Go to D4 . No: Go to D3 .
3. D3 CHECK THE ACTUATORS Measure the resistance between HVAC module C228A-2, circuit CH233 (VT/BN), harness side and HVAC module C228A-12, circuit CH232 (WH/BN), harness side. While measuring the resistance, disconnect the following components one at a time, in order. Stop disconnecting components if the measured resistance rises above 100 ohms. Defrost/panel/floor door actuator C236 Temperature blend door actuator C2092 Did the resistance rise above 100 ohms? Yes: INSTALL a new actuator (the last one to be disconnected). Refer to «CLIMATE CONTROL»(ref-382426) . CONNECT the actuator electrical connector before the HVAC module connector(s). This allows the actuator to be calibrated when the HVAC module is reconnected. TEST the system for normal operation. No: REPAIR circuits CH233 (VT/BN) and CH232 (WH/BN) for a short together. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
4. D4 CHECK THE REFERENCE VOLTAGE CIRCUIT FOR A SHORT TO VOLTAGE Ignition ON. Measure the voltage between ground and HVAC module C228A-12, circuit CH232 (WH/BN), harness side Is any voltage present? Yes: REPAIR circuit CH232 (WH/BN) for a short to voltage. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation. No: Go to D5 .
5. D5 CHECK THE RETURN CIRCUIT FOR A SHORT TO VOLTAGE Ignition ON. Measure the voltage between ground and HVAC module C228A-2, circuit CH233 (VT/BN), harness side Is any voltage present? Yes: REPAIR circuit CH233 (VT/BN) for a short to voltage. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation. No Go to D6 .
6. D6 CHECK THE REFERENCE VOLTAGE CIRCUIT FOR AN OPEN Ignition OFF. Disconnect: Temperature Blend Door Actuator C2092. Measure the resistance between ground and HVAC module C228A-12, circuit CH232 (WH/BN), harness side and temperature blend door actuator C2092-2, circuit CH232 (WH/BN). Is the resistance less than 5 ohms? Yes: Go to D7 . No: REPAIR circuit CH232 (WH/BN) for an open. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
7. D7 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»(ref-382426) . 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.

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

1. DTC 53 (Battery Voltage Low) - The module senses when battery voltage is less than 8 volts for more than 2 seconds.
2. DTC 54 (Battery Voltage High) - The module senses when battery voltage is greater than 16 volts for more than 2 seconds. This pinpoint test is intended to diagnose the following
3. Wiring, terminals or connectors
4. HVAC module
5. Battery
6. Charging system concern

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1. E1 RETRIEVE ALL CMDTCs IN ALL MODULES Ignition ON. Enter the following diagnostic mode on the scan tool: Self Test - All CMDTCs. Are any charging system DTCs present in the PCM?? Yes: Refer to «CHARGING SYSTEM»(ref-382376) for diagnosis of the battery and charging system. No: Go to E2 .
2. E2 CHECK BATTERY CONDITION Ignition OFF. Refer to «BATTERY, MOUNTING AND CABLES»(ref-382392) and carry out the Battery - Condition Test. Does the battery pass the condition test? Yes: If the battery passed the condition test but required a recharge, Refer to «CHARGING SYSTEM»(ref-382376) to diagnose the charging system. CLEAR all Continuous Memory Diagnostic Trouble Codes (CMDTCs). TEST the system for normal operation. If the battery passed the condition test and did not require a recharge, go to E3 . No: INSTALL a new battery. CLEAR all CMDTCs. TEST the system for normal operation.
3. E3 CHECK THE CHARGING SYSTEM VOLTAGE NOTE: Do not allow the engine RPM to exceed above 2,000 RPM while performing this step or the generator may self-excite and result in default charging system output voltage. If engine RPM has exceeded 2,000 RPM, shut the vehicle off and restart the engine before performing this step. Start the engine. Measure the voltage of the battery: For DTC 54 , turn on headlights and HVAC fan on high and run engine at 1,500 RPM for a minimum of 2 minutes. For DTC 53 , turn off all accessories and run the engine at 1,500 RPM for a minimum of 2 minutes. Is the battery voltage between 13 and 15.2 volts? Yes If diagnosing DTC 5-3 , go to E4 . If diagnosing DTC 5-4 , INSTALL a new HVAC module. Refer to «CLIMATE CONTROL»(ref-382426) . CLEAR all CMDTCs . REPEAT the self-test. No: Refer to «CHARGING SYSTEM»(ref-382376) to diagnose the charging system. CLEAR all CMDTCs . TEST the system for normal operation.
4. E4 CHECK THE HVAC MODULE VOLTAGE SUPPLY CIRCUITS 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 E5 . No: REPAIR circuit SBP07 (WH/RD) or CBP21 (BU/GY) for high resistance. CLEAR all CMDTCs . REPEAT the self-test.
5. E5 CHECK THE HVAC MODULE GROUND CIRCUIT 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 E6 . No: REPAIR circuit GD115 (BK/GY) for high resistance. CLEAR all CMDTCs . REPEAT the self-test. TEST the system for normal operation.
6. E6 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»(ref-382426) . 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.

This pinpoint test tests the functions of the HVAC system and identifies the correct HVAC symptom pinpoint test.

This pinpoint test is intended to diagnose the following

1. Incorrect functioning of the HVAC system and/or related components

The HVAC module supplies voltage and ground to the air inlet mode door actuator through the actuator motor circuits to rotate the air inlet mode door actuator. To reverse the air inlet mode door actuator rotation, the HVAC module reverses voltage and ground on the circuits.

When the HVAC is in FLOOR/DEFROST or FLOOR mode, RECIRC is a timed function. When RECIRC is selected, the air inlet mode door remains in recirculated air mode for 5 minutes. After 5 minutes, the RECIRC indicator turns off and the air inlet mode door changes to fresh air mode.

1. DTC 4-2 (Recirculation Motor Driver Circuit/Performance) - This DTC sets when either of the following occurs: The module senses lower than expected voltage on an actuator motor circuit when voltage is applied to drive the motor, indicating a short to ground. The module senses greater than expected voltage on the actuator motor circuit when ground is applied to drive the motor, indicating a short to voltage. This pinpoint test is intended to diagnose the following
2. Wiring, terminals or connectors
3. Air inlet mode door actuator
4. HVAC module
5. Air inlet mode door binding or stuck

Scheme 33

Scheme 34

Scheme 35

Scheme 36

Scheme 37

Scheme 38

1. G1 CHECK THE HVAC MODULE FOR DTCs Ignition ON. Carry out the HVAC module self-test. Check for HVAC DTCs retrieved during the self-test. Is DTC 4-2 present? Yes: Go to G2 . No: Go to G6 .
2. G2 CHECK THE AIR INLET MODE DOOR ACTUATOR MOTOR CIRCUITS FOR A SHORT TO VOLTAGE Ignition OFF. Disconnect: HVAC Module C228A. Ignition ON. Measure the voltage between ground and: HVAC module C228A-9, circuit CH206 (YE/VT), harness side. HVAC module C228A-18, circuit CH208 (GN/OG), harness side. Are any voltages present? Yes: REPAIR circuit CH206 (YE/VT) or CH208 (GN/OG) for a short to voltage. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation. No: Go to G3 .
3. G3 CHECK THE AIR INLET MODE DOOR ACTUATOR MOTOR CIRCUITS FOR A SHORT TO GROUND Ignition OFF. Measure the resistance between ground and: HVAC module C228A-9, circuit CH206 (YE/VT), harness side. HVAC module C228A-18, circuit CH208 (GN/OG), harness side. Are the resistances greater than 10,000 ohms? Yes: Go to G4 . No: REPAIR circuit CH206 (YE/VT) or CH208 (GN/OG) for a short to ground. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
4. G4 CHECK THE AIR INLET MODE DOOR ACTUATOR MOTOR RESISTANCE Measure the resistance between HVAC module C228A-9, circuit CH206 (YE/VT), harness side and HVAC module C228A-18, circuit CH208 (GN/OG), harness side. Is the resistance greater than 30 ohms? Yes: Go to G8 . No: Go to G5 .
5. G5 CHECK THE AIR INLET MODE DOOR ACTUATOR MOTOR CIRCUITS FOR A SHORT TOGETHER Disconnect: Air Inlet Mode Door Actuator C289. Measure the resistance between HVAC module C228A-9, circuit CH206 (YE/VT), harness side and HVAC module C228A-18, circuit CH208 (GN/OG), harness side. Is the resistance greater than 10,000 ohms? Yes: INSTALL a new air inlet actuator. Refer to «CLIMATE CONTROL»(ref-382426) . CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation. No: REPAIR circuits CH208 (GN/OG) and CH206 (YE/VT) for a short together. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
6. G6 CHECK THE AIR INLET MODE DOOR ACTUATOR MOTOR CIRCUITS FOR AN OPEN Ignition OFF. Disconnect: HVAC Module C228A. Disconnect: Air Inlet Mode Door Actuator C289. Measure the resistance between HVAC module C228A-18, circuit CH208 (GN/OG), harness side and air inlet mode door actuator C289-1, circuit CH208 (GN/OG), harness side. Measure the resistance between HVAC module C228A-9, circuit CH206 (YE/VT), harness side and air inlet mode door actuator C289-6, circuit CH206 (YE/VT), harness side. Are the resistances less than 5 ohms? Yes: Go to G7 . No: REPAIR circuit CH206 (YE/VT) or CH208 (GN/OG) for an open. TEST the system for normal operation.
7. G7 CHECK THE AIR INLET MODE DOOR AND LINKAGE Disconnect: Air Inlet Mode Door Actuator C289. REMOVE the air inlet mode door actuator. Refer to «CLIMATE CONTROL»(ref-382426) . INSPECT the air inlet mode door and linkage for a broken, loose or binding condition. Is any binding condition found during inspection? Yes: REPAIR the air inlet mode door or linkage TEST the system for normal operation. No: Go to G8 .
8. G8 CHECK THE AIR INLET MODE DOOR ACTUATOR CONNECTION Disconnect the air inlet mode door actuator connector. Inspect the air inlet door actuator connector for: corrosion. pushed-out terminals. damaged terminals. Connect and correctly seat the actuator connector. Operate the system and verify the concern is still present. Is the concern still present? Yes: Carry out the Air Inlet Mode Door Actuator component test in this information. INSTALL a new air inlet mode door if necessary. Refer to «CLIMATE CONTROL»(ref-382426) . If the actuator tests OK, go to G9 . 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.
9. G9 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»(ref-382426) . 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.

The HVAC module supplies voltage and ground to the defrost/panel/floor mode door actuator motor through the actuator motor circuits to rotate the defrost/panel/floor mode door actuator. To reverse the defrost/panel/floor mode door actuator rotation, the HVAC module reverses voltage and ground on the circuits.

The defrost/panel/floor mode door actuator feedback resistor is supplied a 5-volt reference voltage and ground from the HVAC module. The HVAC module measures the resistance on the defrost/panel/floor mode door actuator feedback circuit to determine the defrost/panel/floor mode door actuator position by the position of the actuator feedback resistor wiper arm.

During an actuator calibration cycle, the HVAC module drives the defrost/panel/floor mode door until the door reaches both internal stops in the HVAC case. If the defrost/panel/floor mode door is temporarily obstructed or binding during a calibration cycle, the HVAC module may interpret this as the actual end of travel for the door. When this condition occurs and the HVAC module commands the actuator to its end of travel, the airflow may not be from the expected outlets.

1. DTC 3-1 (Mode Feedback Circuit/Performance) - The module senses no changes in the feedback circuit when motor movement is commanded and no motor electrical DTCs are present. This indicates an open actuator motor, an open or shorted feedback circuit, an open feedback resistor reference voltage circuit, or an internal electrical or mechanical failure.
2. DTC 3-2 (Mode Motor Driver Circuit/Performance) - The module senses lower than expected voltage on an actuator motor circuit when voltage is applied to drive the motor. This indicates a short to ground or the module senses greater than expected voltage on the actuator motor circuit when ground is applied to drive the motor, indicating a short to voltage.
3. DTC 3-3 (Mode Actuator Calibration Performance) - The module senses the actuator has moved outside its travel limits during calibration. This indicates broken/disconnected linkage or door or an internal mechanical failure. This pinpoint test is intended to diagnose the following
4. Wiring, terminals or connectors
5. Defrost/panel/floor mode door actuator
6. HVAC module
7. Defrost/panel/floor mode door binding or stuck

Scheme 39

Scheme 40

Scheme 41

Scheme 42

Scheme 43

Scheme 44

Scheme 45

Scheme 46

Scheme 47

Scheme 48

Scheme 49

Scheme 50

1. H1 CHECK THE HVAC MODULE FOR DTCs NOTE: If HVAC DTC 4-4 is present, go to «PINPOINT TEST D»(ref-382377-S00862852022011012300000) and diagnose that DTC first. Ignition ON. Carry out the HVAC module self-test. Check for HVAC DTCs retrieved during the self-test. Are HVAC DTCs present? Yes For DTC 3-1 , go to H2 . For DTC 3-2 , go to H9 . For DTC 3-3 , go to H8 . No: Go to H7 .
2. H2 CHECK THE ACTUATOR MOTOR AND CIRCUITS Ignition OFF. Disconnect: HVAC Module C228A. Measure the resistance between HVAC module C228A-7, circuit CH202 (BU/GN), harness side and HVAC module C228A-8, circuit CH203 (GN/BN), harness side. Is the resistance less than 40 ohms? Yes: Go to H4 . No: Go to H3 .
3. H3 CHECK THE DEFROST/PANEL/FLOOR MODE DOOR ACTUATOR Ignition OFF. Disconnect: Defrost/Panel/Floor Mode Door Actuator C236. Carry out the Defrost/Panel/Floor Mode Door Actuator component test in this information. Did the defrost/panel/floor mode door actuator test OK? Yes: REPAIR circuit CH202 (BU/GN) or CH203 (GN/BN) for an open or high resistance. REPEAT the self-test. TEST the system for normal operation. No: Go to H13 .
4. H4 CHECK THE POTENTIOMETER LOW- AND HIGH-SIDE RESISTANCE Measure the high-side resistance between HVAC module C228A-12, circuit CH232 (WH/BN), harness side and HVAC module C228A-1, circuit CH204 (GY/OG), harness side. Measure the low-side resistance between HVAC module C228A-2, circuit CH233 (VT/BN), harness side and HVAC module C228A-1, circuit CH204 (GY/OG), harness side. Are the resistances between 215 and 4,375 ohms? Yes: Go to H5 . No: Carry out the Defrost/Panel/Floor Mode Door Actuator component test in this information. INSTALL a new defrost/panel/floor mode door actuator if necessary. Refer to «CLIMATE CONTROL»(ref-382426) . If the actuator tests OK and: If the high-side resistance only is greater than 4,375 ohms, REPAIR circuit CH232 (WH/BN) for an open. If the high-side resistance only is less than 215 ohms, REPAIR circuits CH204 (GY/OG) and CH232 (WH/BN) for a short together. If the low-side resistance only is greater than 4,375 ohms, REPAIR circuit CH233 (VT/BN) for an open. If the low-side resistance only is less than 215 ohms, REPAIR circuits CH204 (GY/OG) and CH233 (VT/BN) for a short together. If both the high-side and low-side resistance is greater than 4,375 ohms, REPAIR circuit CH204 (GY/OG) for an open. Once the repair is complete, CALIBRATE the actuators. Refer to «CALIBRATING THE HVAC ACTUATORS»(ref-382377-S22132714032011012300000) in this information. TEST the system for normal operation.
5. H5 CHECK THE ACTUATOR FEEDBACK CIRCUIT FOR A SHORT TO VOLTAGE Ignition ON. Measure the voltage between ground and HVAC module C228A-1, circuit CH204 (GY/OG), harness side. Is any voltage present? Yes: REPAIR circuit CH204 (GY/OG) for a short to voltage. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation. No: Go to H6 .
6. H6 CHECK THE ACTUATOR FEEDBACK CIRCUIT FOR A SHORT TO GROUND Ignition OFF. Measure the resistance between ground and HVAC module C228A-1, circuit CH204 (GY/OG), harness side. Are the resistances greater than 10,000 ohms? Yes: Go to H7 . No: REPAIR circuit CH204 (GY/OG) for a short to ground. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
7. H7 CHECK THE DEFROST/PANEL/FLOOR MODE DOOR ACTUATOR OPERATION Ignition OFF. Disconnect: HVAC Module C228A (If not previously disconnected). Measure the resistance between HVAC module C228A-2, circuit CH233 (VT/BN), harness side and HVAC module C228A-1, circuit CH204 (GY/OG), harness side. Connect a fused jumper wire between: HVAC module C228A-10, circuit SBP07 (WH/RD), harness side and HVAC module C228A-7, circuit CH202 (BU/GN), harness side. HVAC module C228A-13, circuit GD115 (BK/GY), harness side and HVAC module C228A-8, circuit CH203 (GN/BN), harness side. Remove the fused jumpers. Connect a fused jumper wire between: HVAC module C228A-13, circuit GD115 (BK/GY), harness side and HVAC module C228A-7, circuit CH202 (BU/GN), harness side. HVAC module C228A-10, circuit SBP07 (WH/RD), harness side and HVAC module C228A-8, circuit CH203 (GN/BN), harness side. Does the resistance smoothly increase to approximately 3,500 ohms and/or decrease to approximately 290 ohms when the jumpers are connected? Yes: Go to H14 . No: Go to H8 .
8. H8 CHECK THE DEFROST/PANEL/FLOOR MODE DOOR AND LINKAGE Disconnect: Defrost/Panel/Floor Mode Door Actuator C236. REMOVE the defrost/panel/floor mode door actuator. Refer to «CLIMATE CONTROL»(ref-382426) . INSPECT the defrost/panel/floor mode door and linkage for a broken, loose or binding condition. Is any condition found during inspection? Yes: REPAIR the defrost/panel/floor mode door or linkage REINSTALL the defrost/panel/floor mode door actuator. CALIBRATE the actuators. Refer to «CALIBRATING THE HVAC ACTUATORS»(ref-382377-S22132714032011012300000) in this information. TEST the system for normal operation. No: Go to H13 .
9. H9 CHECK THE ACTUATOR MOTOR DRIVE CIRCUITS FOR A SHORT TO VOLTAGE Ignition OFF. Disconnect: HVAC Module C228A. Ignition ON. Measure the voltage between ground and: HVAC module C228A-7, circuit CH202 (BU/GN), harness side. HVAC module C228A-8, circuit CH203 (GN/BN), harness side. Are any voltages present? Yes: REPAIR circuit CH202 (BU/GN) or CH203 (GN/BN) for a short to voltage. TEST the system for normal operation. No: Go to H10 .
10. H10 CHECK THE ACTUATOR MOTOR DRIVE CIRCUITS FOR A SHORT TO GROUND Ignition OFF. Measure the resistance between ground and: HVAC module C228A-7, circuit CH202 (BU/GN), harness side. HVAC module C228A-8, circuit CH203 (GN/BN), harness side. Are the resistances greater than 10,000 ohms? Yes: Go to H11 . No: REPAIR circuit CH202 (BU/GN) or CH203 (GN/BN) for a short to ground. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
11. H11 CHECK THE ACTUATOR MOTOR AND CIRCUIT RESISTANCE Measure the resistance between HVAC module C228A-7, circuit CH202 (BU/GN), harness side and HVAC module C228A-8, circuit CH203 (GN/BN), harness side. Is the resistance greater than 30 ohms? Yes: Go to H14 . No: Go to H12 .
12. H12 CHECK THE ACTUATOR MOTOR CIRCUITS FOR A SHORT TOGETHER Disconnect: Defrost/Panel/Floor Mode Door Actuator C236. Measure the resistance between HVAC module C228A-7, circuit CH202 (BU/GN), harness side and HVAC module C228A-8, circuit CH203 (GN/BN), harness side. Is the resistance greater than 10,000 ohms? Yes: Go to H13 . No: REPAIR circuits CH202 (BU/GN) and CH203 (GN/BN) for a short together. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
13. H13 CHECK THE DEFROST/PANEL/FLOOR MODE DOOR ACTUATOR CONNECTION Disconnect the defrost/panel/floor mode door actuator connector. Inspect the defrost/panel/floor mode door actuator connector for: corrosion. pushed-out terminals. damaged terminals. REINSTALL the defrost/panel/floor mode door actuator, If removed. Connect and correctly seat the defrost/panel/floor mode door actuator connector. CALIBRATE the actuators. Refer to «CALIBRATING THE HVAC ACTUATORS»(ref-382377-S22132714032011012300000) in this information. Operate the system and verify the concern is still present. Is the concern still present? Yes: INSTALL a new defrost/panel/floor mode door actuator. Refer to «CLIMATE CONTROL»(ref-382426) . CALIBRATE the actuators. Refer to «CALIBRATING THE HVAC ACTUATORS»(ref-382377-S22132714032011012300000) in this information. 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.
14. H14 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»(ref-382426) . TEST the system for normal operation. No: The system is now operating correctly at this time. The concern may have been caused by a foreign object in the HVAC case or temporary binding that restricted actuator door travel. CHECK any actuator external linkage. If condition recurs, INSPECT actuator linkage and door for binding and CHECK HVAC case for foreign objects.

Coolant flows from the engine through the heater core and back to the engine. Proper coolant temperatures are critical for good heater performance.

This pinpoint test is intended to diagnose the following

1. Plugged or partially plugged heater core
2. Low engine coolant level
3. Temperature blend door actuator
4. Temperature blend door binding or stuck

When A/C is requested the HVAC module grounds a circuit to the Instrument Panel Cluster (IPC). The IPC then sends an A/C request through the High Speed Controller Area Network (HS-CAN) to the PCM.

Voltage is provided to the A/C clutch relay coil and switch contacts. When A/C is requested and A/C line pressures allow, a ground is provided to the A/C clutch relay coil from the PCM, energizing the A/C clutch relay. When the PCM energizes the relay, voltage is supplied to the A/C clutch from the relay. Ground is supplied for the A/C clutch.

The evaporator discharge air temperature sensor is used for A/C compressor cycling. An accurate evaporator temperature is critical for compressor engagement. The PCM uses the temperature measurement to turn the A/C compressor off before the evaporator temperature is cold enough to freeze the condensation on the evaporator core.

When an A/C request is received by the PCM, the A/C compressor clutch only engages the A/C clutch relay if all of the following conditions are met

1. The A/C pressure transducer does not indicate excessively low or high refrigerant pressure. Refer to «SPECIFICATIONS»(ref-382377-S19882702412011012300000) in this information.
2. The PCM does not detect excessively high engine coolant temperature.
3. The PCM does not detect an ambient air temperature below 0C° (32F°).
4. The PCM has not detected a Wide Open Throttle (WOT) condition.
5. The HVAC module does not detect an evaporator discharge air temperature below 0.6C° (33F°).
6. DTC 52 (A/C Select Drive Circuit/Performance) - This DTC sets when any of the following occur during a self-test: The module senses ground on the A/C request circuit when the circuit is not grounded by the HVAC module, indicating a short directly to ground. The module senses voltage on the A/C request circuit when the circuit is grounded by the HVAC module, indicating a short directly to voltage. The module senses no voltage on the A/C request circuit when the relay is not grounded by the HVAC module, indicating an open. This pinpoint test is intended to diagnose the following
7. Fuse(s)
8. Wiring, terminals or connectors
9. A/C system discharged/low charge
10. PCM
11. HVAC module
12. IPC
13. Evaporator discharge air temperature sensor
14. A/C pressure transducer
15. A/C compressor clutch field coil
16. A/C clutch relay
17. A/C compressor clutch air gap

When A/C is requested the HVAC module grounds a circuit to the Instrument Panel Cluster (IPC). The IPCs then ends an A/C request through the High Speed Controller Area Network (HS-CAN) to the PCM.

Voltage is provided to the A/C clutch relay coil and switch contacts. When A/C is requested and A/C line pressures allow, a ground is provided to the A/C clutch relay coil from the PCM, energizing the A/C clutch relay. When the PCM energizes the relay, voltage is supplied to the A/C clutch from the relay. Ground is supplied for the A/C clutch.

The evaporator discharge air temperature sensor is used for A/C compressor cycling. An accurate evaporator temperature is critical for compressor engagement. The PCM uses the temperature measurement to turn the A/C compressor off before the evaporator temperature is cold enough to freeze the condensation on the evaporator core.

This pinpoint test is intended to diagnose the following

1. Wiring, terminals or connectors
2. PCM
3. IPC
4. Evaporator discharge air temperature sensor
5. A/C clutch relay
6. A/C compressor clutch air gap

Scheme 51

Scheme 52

Scheme 53

Scheme 54

1. K1 CHECK THE A/C EVAPORATOR TEMPERATURE (EVAP_TEMP) INSTRUMENT PANEL CLUSTER (IPC) PID Ignition ON. Allow the vehicle exterior and interior to stabilize to the ambient temperature. Enter the following diagnostic mode on the scan tool: IPC DataLogger. Monitor the EVAP_TEMP IPC PID Does the EVAP_TEMP IPC PID read similar to the ambient temperature? Yes: Go to K2 . No: Go to K8 .
2. K2 CHECK AIR CONDITIONING COMPRESSOR COMMANDED STATE (ACC_CMD) PCM PID WITH THE A/C OFF Enter the following diagnostic mode on the scan tool: PCM DataLogger. Select PANEL and press the A/C button (indicator off) on the HVAC controls. Monitor the ACC_CMD PCM PID Does the ACC_CMD PCM PID read OFF? Yes: Go to K3 . No: Go to K10 .
3. K3 CHECK THE A/C RELAY Ignition OFF. Disconnect: A/C Clutch Relay. Start the engine. OBSERVE A/C compressor clutch operation. Does the A/C compressor clutch disengage? Yes: Go to K4 . No: Go to K6 .
4. K4 CHECK THE A/C CLUTCH RELAY NOTE: The following step uses a test light to simulate normal circuit loads. Use only the test light recommended in the Special Tools table at the beginning of this information or equivalent. To avoid connector terminal damage, use the Flex Probe Kit for the test light probe connection to the vehicle. Do not use the test light probe directly on any connector. Connect a 12-volt test light between A/C clutch relay socket pin 1, circuit CBP02 (GN) and A/C clutch relay socket pin 2, circuit CH302 (WH/BN). Does the test light illuminate? Yes: Go to K5 . No: INSTALL a new A/C clutch relay. TEST the system for normal operation.
5. K5 CHECK THE A/C CLUTCH RELAY COIL SWITCHED GROUND CIRCUIT FOR A SHORT TO GROUND Ignition OFF. Disconnect: PCM C175B. Measure the resistance between ground and PCM C175B-25, circuit CH302 (WH/BN), harness side. Is the resistance greater than 10,000 ohms? Yes: Go to K10 . No: REPAIR circuit CH302 (WH/BN) for a short to ground. TEST the system for normal operation.
6. K6 CHECK FOR VOLTAGE TO THE A/C COMPRESSOR CLUTCH FIELD COIL Ignition OFF. Disconnect: A/C Compressor Clutch Field Coil C100. Ignition ON. Measure the voltage between A/C compressor clutch field coil C100-1, circuit CH401 (VT/WH), harness side and ground. Is any voltage present? Yes: REPAIR circuit CH401 (VT/WH) for a short to voltage. TEST the system for normal operation. No: Go to K7 .
7. K7 CHECK THE A/C COMPRESSOR CLUTCH AIR GAP Measure the A/C compressor clutch air gap at 3 equally spaced locations between the clutch hub and the A/C compressor clutch pulley. Is the A/C compressor clutch air gap average less than 0.3 mm (0.012 in)? Yes: ADJUST the A/C compressor clutch gap. Refer to «AIR CONDITIONING (A/C) CLUTCH AIR GAP ADJUSTMENT»(ref-382377-S14463828112011012300000) in this information. TEST the system for normal operation. No: INSTALL a new A/C compressor clutch. Refer to «CLIMATE CONTROL»(ref-382426) . TEST the system for normal operation.
8. K8 CHECK THE EVAPORATOR TEMPERATURE AIR TEMPERATURE SENSOR Ignition OFF. Disconnect: Evaporator Discharge Air Temperature Sensor C296. Carry out the Evaporator Discharge Air Temperature Sensor component test in this information. Did the evaporator discharge air temperature sensor test OK? Yes: Go to K9 . No: INSTALL a new evaporator discharge air temperature sensor. Refer to «CLIMATE CONTROL»(ref-382426) . TEST the system for normal operation.
9. K9 CHECK THE IPC CONNECTION Disconnect all the IPC connectors. Inspect the IPC connectors for: corrosion. pushed-out terminals. damaged terminals. Connect and correctly seat all the IPC connectors. Operate the system and verify the concern is still present. Is the concern still present? Yes: INSTALL a new IPC . Refer to «INSTRUMENTATION, MESSAGE CENTER, AND WARNING CHIMES»(ref-382387) . 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. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
10. K10 CHECK THE PCM CONNECTION Disconnect all the PCM connectors. Inspect the PCM connectors for: corrosion. pushed-out terminals. damaged terminals. Connect and correctly seat all the PCM connectors. Operate the system and verify the concern is still present. Is the concern still present? Yes: INSTALL a new PCM. Refer to «ELECTRONIC ENGINE CONTROLS»(ref-382403) . 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.

Under normal operation, when A/C is requested the HVAC module grounds a circuit to the Instrument Panel Cluster (IPC). The IPC then sends an A/C request through the High Speed Controller Area Network (HS-CAN) to the PCM.

1. DTC 52 (A/C Select Drive Circuit/Performance) - This DTC sets when any of the following occur during a self-test: The module senses ground on the A/C request circuit when the circuit is not grounded by the HVAC module, indicating a short directly to ground. The module senses voltage on the A/C request circuit when the circuit is grounded by the HVAC module, indicating a short directly to voltage. The module senses no voltage on the A/C request circuit when the relay is not grounded by the HVAC module, indicating an open.

This pinpoint test is intended to diagnose the following

1. Wiring, terminals or connectors
2. PCM
3. HVAC module

The HVAC module supplies voltage and ground to the temperature blend door actuator motor through the actuator motor circuits to rotate the temperature blend door actuator. To reverse the temperature blend door actuator rotation, the HVAC module reverses the voltage and ground on the circuits.

The temperature blend door actuator feedback resistor is supplied a 5-volt reference voltage and ground from the HVAC module. The HVAC module measures the resistance on the temperature blend door actuator feedback circuit to determine the temperature blend door actuator position by the position of the actuator feedback resistor wiper arm.

During an actuator calibration cycle, the HVAC module drives the temperature blend door until the door reaches both internal stops in the HVAC case. If the temperature blend door is temporarily obstructed or binding during a calibration cycle, the HVAC module may interpret this as the actual end of travel for the door. When this condition occurs and the HVAC module commands the actuator to its end of travel, the airflow may not be the expected temperature.

1. DTC 2-1 (Blend Feedback Circuit/Performance) - The module senses no changes in the feedback circuit when motor movement is commanded and no motor electrical DTCs are present. This indicates an open actuator motor, an open or shorted feedback circuit, an open feedback resistor reference voltage circuit, or an internal electrical or mechanical failure.
2. DTC 2-2 (Blend Motor Driver Circuit/Performance) - The module senses lower than expected voltage on an actuator motor circuit when voltage is applied to drive the motor. This indicates a short to ground or the module senses greater than expected voltage on the actuator motor circuit when ground is applied to drive the motor, indicating a short to voltage.
3. DTC 2-3 (Blend Actuator Calibration Performance) - The module senses the actuator has moved outside its travel limits during calibration. This indicates broken/disconnected linkage or door or an internal mechanical failure.

This pinpoint test is intended to diagnose the following

1. Wiring, terminals or connectors
2. Temperature blend door actuator
3. HVAC module
4. Temperature blend door is binding or stuck

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1. M1 CHECK THE HVAC MODULE FOR DTCs NOTE: If HVAC DTC 4-4 is present, go to «PINPOINT TEST D»(ref-382377-S00862852022011012300000) and diagnose that DTC first. Ignition ON. Carry out the HVAC module self-test. Check for HVAC DTCs retrieved during the self-test. Are HVAC DTCs present? Yes For DTC 2-1 , go to M2 . For DTC 2-2 , go to M9 . For DTC 2-3 , go to M8 . No: Go to M7 .
2. M2 CHECK THE ACTUATOR MOTOR AND CIRCUITS Ignition OFF. Disconnect: HVAC Module C228A. Measure the resistance between HVAC module C228A-17, circuit CH235 (BU), harness side and HVAC module C228A-19, circuit CH236 (WH), harness side. Is the resistance less than 40 ohms? Yes: Go to M4 . No: Go to M3 .
3. M3 CHECK THE TEMPERATURE BLEND DOOR ACTUATOR Ignition OFF. Disconnect: Temperature Blend Door Actuator C2092. Carry out the Temperature Blend Door Actuator component test in this information. Did the temperature blend door actuator test OK? Yes: REPAIR circuit CH235 (BU) or CH236 (WH) for an open or high resistance. REPEAT the self-test. TEST the system for normal operation. No: Go to M13 .
4. M4 CHECK THE POTENTIOMETER LOW- AND HIGH-SIDE RESISTANCE Measure the high-side resistance between HVAC module C228A-12, circuit CH232 (WH/BN), harness side and HVAC module C228A-11, circuit CH206 (YE/VT), harness side. Measure the low-side resistance between HVAC module C228A-2, circuit CH233 (VT/BN), harness side and HVAC module C228A-11, circuit CH206 (YE/VT), harness side. Are the resistances between 215 and 4,375 ohms? Yes: Go to M5 . No: Carry out the Temperature Blend Door Actuator component test in this information. INSTALL a new defrost/panel/floor mode door actuator if necessary. Refer to «CLIMATE CONTROL»(ref-382426) . If the actuator tests OK and: If the high-side resistance only is greater than 4,375 ohms, REPAIR circuit CH232 (WH/BN) for an open. If the high-side resistance only is less than 215 ohms, REPAIR circuits CH206 (YE/VT) and CH232 (WH/BN) for a short together. If the low-side resistance only is greater than 4,375 ohms, REPAIR circuit CH233 (VT/BN) for an open. If the low-side resistance only is less than 215 ohms, REPAIR circuits CH206 (YE/VT) and CH233 (VT/BN) for a short together. If both the high-side and low-side resistance is greater than 4,375 ohms, REPAIR circuit CH206 (YE/VT) for an open. Once the repair is complete, CALIBRATE the actuators. Refer to «CALIBRATING THE HVAC ACTUATORS»(ref-382377-S22132714032011012300000) in this information. TEST the system for normal operation.
5. M5 CHECK THE ACTUATOR FEEDBACK CIRCUIT FOR A SHORT TO VOLTAGE Ignition ON. Measure the voltage between ground and HVAC module C228A-11, circuit CH206 (YE/VT), harness side. Is any voltage present? Yes: REPAIR circuit CH206 (YE/VT) for a short to voltage. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation. No: Go to M6 .
6. M6 CHECK THE ACTUATOR FEEDBACK CIRCUIT FOR A SHORT TO GROUND Ignition OFF. Measure the resistance between ground and HVAC module C228A-11, circuit CH206 (YE/VT), harness side. Are the resistances greater than 10,000 ohms? Yes: Go to M7 . No: REPAIR circuit CH206 (YE/VT) or CH233 (VT/BN) for a short to ground. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
7. M7 CHECK THE TEMPERATURE BLEND DOOR ACTUATOR OPERATION Ignition OFF. Disconnect: HVAC Module C228A (If not previously disconnected). Measure the resistance between HVAC module C228A-2, circuit CH233 (VT/BN), harness side and HVAC module C228A-11, circuit CH206 (YE/VT), harness side. Connect a fused jumper wire between: HVAC module C228A-10, circuit SBP07 (WH/RD), harness side and HVAC module C228A-17, circuit CH235 (BU), harness side. HVAC module C228A-13, circuit GD115 (BK/GY), harness side and HVAC module C228A-19, circuit CH236 (WH), harness side. Remove the fused jumpers. Connect a fused jumper wire between: HVAC module C228A-13, circuit GD115 (BK/GY), harness side and HVAC module C228A-17, circuit CH235 (BU), harness side. HVAC module C228A-10, circuit SBP07 (WH/RD), harness side and HVAC module C228A-19, circuit CH236 (WH), harness side. Does the resistance smoothly increase to approximately 3,500 ohms and/or decrease to approximately 290 ohms when the jumpers are connected? Yes: Go to M14 . No: Go to M8 .
8. M8 CHECK THE TEMPERATURE BLEND DOOR AND LINKAGE Disconnect: Temperature Blend Door Actuator C2092. REMOVE the temperature blend door actuator. Refer to «CLIMATE CONTROL»(ref-382426) . INSPECT the temperature blend door and linkage for a broken, loose or binding condition. Is any condition found during inspection? Yes: REPAIR the temperature blend door or linkage REINSTALL the temperature blend door actuator. CALIBRATE the actuators. Refer to «CALIBRATING THE HVAC ACTUATORS»(ref-382377-S22132714032011012300000) in this information. TEST the system for normal operation. No: Go to M13 .
9. M9 CHECK THE ACTUATOR MOTOR DRIVE CIRCUITS FOR A SHORT TO VOLTAGE Ignition OFF. Disconnect: HVAC Module C228A. Ignition ON. Measure the voltage between ground and: HVAC module C228A-17, circuit CH235 (BU), harness side. HVAC module C228A-19, circuit CH236 (WH), harness side. Are any voltages present? Yes: REPAIR circuit CH235 (BU) or CH236 (WH) for a short to voltage. TEST the system for normal operation. No: Go to M10 .
10. M10 CHECK THE ACTUATOR MOTOR DRIVE CIRCUITS FOR A SHORT TO GROUND Ignition OFF. Measure the resistance between ground and: HVAC module C228A-17, circuit CH235 (BU), harness side. HVAC module C228A-19, circuit CH236 (WH), harness side. Are the resistances greater than 10,000 ohms? Yes: Go to M11 . No: REPAIR circuit CH235 (BU) or CH236 (WH) for a short to ground. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
11. M11 CHECK THE ACTUATOR MOTOR AND CIRCUIT RESISTANCE Measure the resistance between HVAC module C228A-17, circuit CH235 (BU), harness side and HVAC module C228A-19, circuit CH236 (WH), harness side. Is the resistance greater than 10,000 ohms? Yes: Go to M14 . No: Go to M12 .
12. M12 CHECK THE ACTUATOR MOTOR CIRCUITS FOR A SHORT TOGETHER Disconnect: Temperature Blend Door Actuator C2092. Measure the resistance between HVAC module C228A-17, circuit CH235 (BU), harness side and HVAC module C228A-19, circuit CH236 (WH), harness side. Is the resistance greater than 10,000 ohms? Yes: Go to M13 . No: REPAIR circuits CH235 (BU) and CH236 (WH) for a short together. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
13. M13 CHECK THE ACTUATOR CONNECTION Disconnect the temperature blend door actuator connector. Inspect the temperature blend door actuator connector for: corrosion. pushed-out terminals. damaged terminals. REINSTALL the temperature blend door actuator, If removed. Connect and correctly seat the temperature blend door actuator connector. CALIBRATE the actuators. Refer to «CALIBRATING THE HVAC ACTUATORS»(ref-382377-S22132714032011012300000) in this information. Operate the system and verify the concern is still present. Is the concern still present? Yes: INSTALL a new temperature blend door actuator. Refer to «CLIMATE CONTROL»(ref-382426) . CALIBRATE the actuators. Refer to «CALIBRATING THE HVAC ACTUATORS»(ref-382377-S22132714032011012300000) in this information. 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.
14. M14 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»(ref-382426) . TEST the system for normal operation. No: The system is now operating correctly at this time. The concern may have been caused by a foreign object in the HVAC case or temporary binding that restricted actuator door travel. CHECK any actuator external linkage. If condition recurs, INSPECT actuator linkage and door for binding and CHECK HVAC case for foreign objects.

The blower motor relay coil and relay switch contacts receive voltage. The blower motor relay is energized when the coil receives ground from the HVAC module, if the HVAC power is on. When the relay coil is energized, voltage is delivered to the blower motor. Ground for the blower motor is provided from the blower resistor or the blower switch (HI). The blower resistor is grounded through the blower motor switch. The blower motor switch is grounded. The blower motor switch is part of the HVAC module and can not be replaced separately.

1. DTC 51 (Blower Relay Driver Circuit/Performance) - This DTC sets when any of the following occur: The module senses ground on the relay coil ground circuit when the relay is not grounded by the HVAC module, indicating a short directly to ground. The module senses voltage on the relay coil ground circuit when the relay is grounded by the HVAC module, indicating a short directly to voltage. The module senses no voltage on the relay coil ground circuit when the relay is not grounded by the HVAC module, indicating an open.

This pinpoint test is intended to diagnose the following

1. Fuse
2. Wiring, terminals or connectors
3. Blower motor
4. Blower motor relay
5. HVAC module

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1. N1 CHECK THE HVAC MODULE FOR DTCs Ignition ON. Carry out the HVAC module self-test. Check for HVAC DTCs retrieved during the self-test. Is DTC 51 present? Yes: Go to N2 . No: Go to N6 .
2. N2 CHECK THE BLOWER MOTOR RELAY COIL SUPPLY VOLTAGE Ignition OFF. Disconnect: Blower Motor Relay. Ignition ON. Measure the voltage between blower motor relay socket pin 1, circuit CBP21 (BU/GY) and ground. Is the voltage greater than 10 volts? Yes: Go to N3 . No: REPAIR circuit CBP21 (BU/GY) for an open. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
3. N3 CHECK THE BLOWER MOTOR RELAY COIL NOTE: The following step uses a test light to simulate normal circuit loads. Use only the test light recommended in the Special Tools table at the beginning of this information or equivalent. To avoid connector terminal damage, use the Flex Probe Kit for the test light probe connection to the vehicle. Do not use the test light probe directly on any connector. Select PANEL on the HVAC controls. Connect a 12-volt test light between blower motor relay socket pin 1, circuit CBP21 (BU/GY) and blower motor relay socket pin 2, circuit CH123 (VT/GN). Does the test light illuminate? Yes: INSTALL a new blower motor relay. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation. No: Go to N4 .
4. N4 CHECK THE BLOWER MOTOR RELAY COIL GROUND CIRCUIT FOR A SHORT TO VOLTAGE Ignition OFF. Disconnect: HVAC Module C228A. Ignition ON. Measure the voltage between blower motor relay socket pin 2, circuit CH123 (VT/GN) and ground. Is any voltage present? Yes: REPAIR circuit CH123 (VT/GN) for a short to voltage. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation. No: Go to N5 .
5. N5 CHECK THE BLOWER MOTOR RELAY COIL GROUND CIRCUIT FOR AN OPEN Ignition OFF. Measure the resistance between blower motor relay socket pin 2, circuit CH123 (VT/GN) and HVAC module C228A-3, circuit CH123 (VT/GN), harness side. Is the resistance less than 5 ohms? Yes: Go to N12 . No: REPAIR circuit CH123 (VT/GN) for an open. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
6. N6 CHECK THE BLOWER MOTOR RELAY SWITCH CONTACTS SUPPLY VOLTAGE Ignition OFF. Disconnect: Blower Motor Relay. Ignition ON. Measure the voltage between blower motor relay socket pin 3, circuit SBB04 (GN/RD) and ground. Is the voltage greater than 10 volts? Yes: Go to N7 . No: VERIFY Battery Junction Box (BJB) fuse 4 (40A) is OK. If OK, REPAIR circuit SBB04 (GN/RD) for an open. TEST the system for normal operation. If not OK, refer to the appropriate SYSTEM WIRING DIAGRAMS article to identify the possible causes of the circuit short.
7. N7 CHECK THE BLOWER MOTOR RELAY Select the highest blower motor speed on HVAC controls. Connect a fused jumper lead between blower motor relay socket pin 3, circuit SBB04 (GN/RD) and blower motor relay socket pin 5, circuit CH402 (YE/GN). Does the blower motor operate? Yes: INSTALL a new blower motor relay. TEST the system for normal operation. No: Go to N8 .
8. N8 CHECK THE BLOWER MOTOR GROUND CIRCUIT Ignition OFF. Disconnect: Blower Motor C2004. Turn the blower motor switch to the HI position. Measure the resistance between blower motor connector C2004-2, circuit CH430 (VT/OG), harness side and ground. Is the resistance less than 5 ohms? Yes: Go to N9 . No: Go to N10 .
9. N9 CHECK THE BLOWER MOTOR VOLTAGE CIRCUIT FOR AN OPEN Measure the resistance between blower motor relay socket pin 5, circuit CH402 (YE/GN) and blower motor C2004-1, circuit CH402 (YE/GN), harness side. Is the resistance less than 5 ohms? Yes: INSTALL a new blower motor. TEST the system for normal operation. No: REPAIR circuit CH402 (YE/GN) for an open. TEST the system for normal operation.
10. N10 CHECK THE BLOWER MOTOR GROUND CIRCUIT FOR AN OPEN Disconnect: HVAC Module C228B. Measure the resistance between HVAC module C228B-6, circuit CH430 (VT/OG), harness side and blower motor C2004-2, circuit CH430 (VT/OG), harness side. Is the resistance less than 5 ohms? Yes: Go to N11 . No: REPAIR circuit CH430 (VT/OG) for an open. TEST the system for normal operation.
11. N11 CHECK THE BLOWER MOTOR SWITCH GROUND CIRCUIT FOR AN OPEN Measure the resistance between HVAC module C228B-3, circuit GD115 (BK/GY), harness side and ground. Is the resistance less than 5 ohms? Yes: Go to N12 . No: REPAIR circuit GD115 (BK/GY) for an open. TEST the system for normal operation.
12. N12 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»(ref-382426) . 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. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.

Under normal operation, the blower motor is provided a ground through part of the blower resistor in LO, MED-LO and MED-HI blower setting. The blower motor resistor is grounded through the blower motor switch in any setting except HI. In HI, the blower motor is grounded directly through the blower motor switch. The blower switch is provided a ground. The blower motor switch is part of the HVAC module and can not be replaced separately.

1. DTC 51 (Blower Relay Driver Circuit/Performance) - This DTC sets when any of the following occur: The module senses ground on the relay coil ground circuit when the relay is not grounded by the HVAC module, indicating a short directly to ground. The module senses voltage on the relay coil ground circuit when the relay is grounded by the HVAC module, indicating a short directly to voltage. The module senses no voltage on the relay coil ground circuit when the relay is not grounded by the HVAC module, indicating an open.

This pinpoint test is intended to diagnose the following

1. Wiring, terminals or connectors
2. Blower motor resistor
3. HVAC module

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1. O1 CHECK THE HVAC MODULE FOR DTCs Ignition ON. Carry out the HVAC module self-test. Check for HVAC DTCs retrieved during the self-test. Is DTC 51 present? Yes: REPAIR circuit CH123 (VT/GN) for a short to ground. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation. No: Go to O2 .
2. O2 CHECK THE BLOWER MOTOR OPERATION Turn the function selector switch to the FLOOR position. Select all blower speed positions. Does the blower motor operate in any position? Yes: If the blower motor will not turn off, REPAIR circuit CH402 (YE/GN) for a short to voltage. TEST the system for normal operation. If the blower motor does not operate in HI setting only, go to O3 . If the blower motor does not operate in LO, MED-LO or MED-HI setting only, go to O4 . If the blower motor operates in HI setting only, go to O6 . For all other symptoms, go to O7 . No: Go to «PINPOINT TEST N»(ref-382377-S14892464892011012300000) .
3. O3 CHECK THE BLOWER MOTOR GROUND CIRCUIT TO THE BLOWER MOTOR SWITCH FOR AN OPEN Ignition OFF. Disconnect: HVAC Module C228B. Disconnect: Blower Motor C2004. Measure the resistance between HVAC module C228B-6, circuit CH430 (VT/OG), harness side and blower motor C2004-2, circuit CH430 (VT/OG), harness side. Is the resistance less than 5 ohms? Yes: Go to O9 . No: REPAIR circuit CH430 (VT/OG) for an open. TEST the system for normal operation.
4. O4 CHECK THE BLOWER MOTOR RESISTOR NOTE: The following step uses a test light to simulate normal circuit loads. Use only the test light recommended in the Special Tools table at the beginning of this information. To avoid connector terminal damage, use the Flex Probe Kit for the test light probe connection to the vehicle. Do not use the test light probe directly on any connector. Ignition OFF. Disconnect: Blower Motor Resistor C293. Ignition ON. Turn the function selector switch to the FLOOR position. For LO inoperative For LO inoperative : With the blower motor switch in the LO speed position, connect a 12-volt test light between blower motor resistor C293-2, circuit CH430 (VT/OG), harness side and blower motor resistor C293-4, circuit CH427 (BN), harness side. For MED-LO inoperative For MED-LO inoperative : With the blower motor switch in the MED-LO speed position, connect a 12-volt test light between blower motor resistor C293-2, circuit CH430 (VT/OG), harness side and blower motor resistor C293-1, circuit CH428 (GN/WH), harness side. For MED-HI inoperative For MED-HI inoperative : With the blower motor switch in the MED-HI speed position, connect a 12-volt test light between blower motor resistor C293-2, circuit CH430 (VT/OG), harness side and blower motor resistor C293-3, circuit CH429 (GY/BN), harness side. Does the test light illuminate? Yes: INSTALL a new blower motor resistor. Refer to «CLIMATE CONTROL»(ref-382426) . TEST the system for normal operation. No: Go to O5 .
5. O5 CHECK THE BLOWER MOTOR RESISTOR TO BLOWER MOTOR SWITCH CIRCUITS Disconnect: HVAC Module C228B. For LO inoperative For LO inoperative , measure the resistance between HVAC module C228B-1, circuit CH427 (BN), harness side and blower motor resistor C293-4, circuit CH427 (BN), harness side. For MED-LO inoperative For MED-LO inoperative , measure the resistance between HVAC module C228B-4, circuit CH428 (GN/WH), harness side and blower motor resistor C293-1, circuit CH428 (GN/WH), harness side. For MED-HI inoperative For MED-HI inoperative , measure the resistance between HVAC module C228B-5, circuit CH429 (GY/BN), harness side and blower motor resistor C293-3, circuit CH429 (GY/BN), harness side. Is the resistance less than 5 ohms? Yes: Go to O9 . No: REPAIR circuit CH427 (BN), CH428 (GN/WH) or CH429 (GY/BN) for an open. TEST the system for normal operation.
6. O6 CHECK THE BLOWER MOTOR GROUND CIRCUIT TO THE BLOWER MOTOR RESISTOR FOR AN OPEN Ignition OFF. Disconnect: Blower Motor C2004. Disconnect: Blower Motor Resistor C293. Measure the resistance between blower motor resistor C293-2, circuit CH430 (VT/OG), harness side and blower motor C2004-2, circuit CH430 (VT/OG), harness side. Is the resistance less than 5 ohms? Yes: INSTALL a new blower motor resistor. Refer to «CLIMATE CONTROL»(ref-382426) . TEST the system for normal operation. No: REPAIR circuit CH430 (VT/OG) for an open. TEST the system for normal operation.
7. O7 CHECK THE BLOWER MOTOR RESISTOR CIRCUITS FOR A SHORT TO GROUND Ignition OFF. Disconnect: Blower Motor C2004. Disconnect: Blower Motor Resistor C293. Disconnect: HVAC Module C228B. Measure the resistance between ground and blower motor resistor: C293-1, circuit CH428 (GN/WH), harness side. C293-3, circuit CH429 (GY/BN), harness side. C293-2, circuit CH430 (VT/OG), harness side. Are the resistances greater than 10,000 ohms? Yes: Go to O8 . No: REPAIR the affected circuit for a short to ground. TEST the system for normal operation.
8. O8 CHECK THE BLOWER MOTOR RESISTOR CIRCUITS FOR SHORTS TOGETHER Measure the resistance between blower motor resistor C293, harness side using the following chart: TERMINAL RESISTANCE REFERENCE Blower Motor Resistor Circuit Blower Motor Resistor Circuit C293-1 CH428 (GN/WH) C293-2 CH430 (VT/OG) C293-1 CH428 (GN/WH) C293-3 CH429 (GY/BN) C293-1 CH428 (GN/WH) C293-4 CH427 (BN) C293-2 CH430 (VT/OG) C293-3 CH429 (GY/BN) C293-2 CH430 (VT/OG) C293-4 CH427 (BN) C293-3 CH429 (GY/BN) C293-4 CH427 (BN) Are the resistances greater than 10,000 ohms? Yes: Go to O9 . No: REPAIR the affected circuits. TEST the system for normal operation.
9. O9 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»(ref-382426) . 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. CLEAR the DTCs. REPEAT the self-test. TEST the system for 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

1. Wiring, terminals or connectors
2. HVAC module
3. Battery
4. Charging system concern

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1. 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.
2. 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.
3. 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»(ref-382426) . 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.

Refrigerant Identification

1. NOTE: A Refrigerant Blend Identifier with Printer must be used to identify gas samples taken directly from the refrigeration system or storage containers prior to recovering or charging the refrigerant system. Follow the instructions included with the Refrigerant Blend Identifier with Printer to obtain the sample for testing.
2. The Refrigerant Blend Identifier with Printer will display one of the following: If the purity level of R-134a is 98% or greater by weight, the green PASS LED will light. The weight concentrations of R-134a, R-12, R-22, hydrocarbons and air will be displayed on the digital display. If refrigerant R-134a does not meet the 98% purity level, the red FAIL LED will light and an alarm will sound alerting the user of potential hazards. The weight concentrations of R-134a, R-12, R-22 and hydrocarbons will be displayed on the digital display. If hydrocarbon concentrations are 2% or greater by weight, the red FAIL LED will light, "Hydrocarbon High" will be displayed on the digital display, and an alarm will sound alerting the user of potential hazards. The weight concentrations of R-134a, R-12, R-22 and hydrocarbons will also be displayed on the digital display.
3. The percentage of air contained in the sample will be displayed if the R-134a content is 98% or greater. The Refrigerant Blend Identifier with Printer eliminates the effect of air when determining the refrigerant sample content because air is not considered a contaminant, although air can affect A/C system performance. When the Refrigerant Blend Identifier with Printer has determined that a refrigerant source is pure (R-134a is 98% or greater by weight) and air concentration levels are 2% or greater by weight, it will prompt the user if an air purge is desired.
4. If contaminated refrigerant is detected, repeat the refrigerant identification test to verify that the refrigerant is indeed contaminated.