HVAC Climate Control System - General Information and Diagnostics: Overview Ford Focus II рестайлинг

Climate Control System Operation

Note. To avoid damaging the vehicle or air conditioning (A/C) components, the following precautions must be observed.

1. The A/C refrigerant of all vehicles must be identified and analyzed prior to refrigerant charging. Failure to do so can contaminate the shop bulk refrigerant and other vehicles.
2. 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.
3. 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.
4. Use only R-134a refrigerant. Due to environmental concerns, when the A/C system is drained, the refrigerant must be collected 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.
5. Refrigerant R-134a 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.
6. A number of manufacturers are producing refrigerant products that are described as direct substitutes for refrigerant 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 refrigerant R-134a.

Note. To avoid contamination of the air conditioning (A/C) system, the following precautions must be observed.

1. Never open or loosen a connection before recovering the refrigerant.
2. When loosening a connection, if any residual pressure is evident, allow it to leak out before opening the fitting.
3. Evacuate a system that has been opened to install a new component or one that has discharged through leakage before charging.
4. Seal open fittings with a cap or plug immediately after disconnecting a component from the system.
5. Clean the outside of the fittings thoroughly before disconnecting a component from the system.
6. Do not remove the sealing caps from a new component until ready to install.
7. 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.
8. Install a new O-ring seal before connecting an open fitting. Coat the fitting and O-ring seal with PAG oil before connecting.
9. When installing a refrigerant line, avoid sharp bends. Position the line away from the exhaust or any sharp edges that can chafe the line.
10. Tighten threaded fittings only to specifications. The steel and aluminum fittings used in the refrigerant system will not tolerate overtightening.
11. When disconnecting a fitting, use a wrench on both halves of the fitting to prevent twisting of the refrigerant lines or tubes.
12. 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 system 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. Blower switch
11. Temperature blend door actuator
12. Floor/defrost/panel door actuator
13. Air inlet door actuator
14. Blower motor resistor or speed control module
15. Blower motor
16. Evaporator discharge air temperature sensor

Normal Operation

Under normal operation, the A/C pressure transducer receives a ground from the PCM through circuit RE407 (YE/VT). A 5-volt reference voltage is supplied to the A/C pressure transducer from the PCM through circuit LE424 (YE/GN). The A/C pressure transducer sends a voltage to the PCM through circuit VH433 (VT/OG) to indicate the A/C pressure.

1. DTC P0532 A/C Pressure Refrigerant Sensor A Circuit Low - The A/C pressure transducer inputs a voltage to the PCM. If the voltage is below the calibrated level, this DTC sets.
2. DTC P0533 A/C Pressure Refrigerant Sensor A Circuit High - The A/C pressure transducer inputs a voltage to the PCM. If the voltage is above the calibrated level, this DTC sets.

This pinpoint test is intended to diagnose the following

1. Wiring, terminals or connectors
2. A/C pressure transducer
3. PCM

Under normal operation, 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 through circuit CH302 (WH/BN), energizing the A/C clutch relay.

1. DTC P0645 - A/C Clutch Relay Control Circuit - The DTC sets when the PCM grounds the relay circuit, excessive current draw is detected on the relay circuit or, with the relay circuit not grounded by the PCM, voltage is not detected on the relay circuit the PCM expects to detect voltage coming through the relay coil to the relay circuit.

This pinpoint test is intended to diagnose the following

1. Wiring, terminals or connectors
2. A/C clutch relay
3. PCM

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1. B1 CHECK THE VOLTAGE TO THE A/C CLUTCH RELAY Key in OFF position. Disconnect: A/C Clutch Relay Key in ON position. Measure the voltage between ground and the A/C clutch relay socket . Is the voltage greater than 10 volts? YES : CARRY OUT the A/C clutch relay component test. REFER to appropriate COMPONENT TESTING article. If the relay tests OK, go to B2 . NO : INSTALL a new Battery Junction Box (BJB). CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
2. B2 CHECK CIRCUIT CH302 (WH/BN) FOR A SHORT TO VOLTAGE Key in OFF position. Disconnect: PCM C175b Key in ON position. Measure the voltage between ground and PCM C175b-2, 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 : Go to B3 .
3. B3 CHECK CIRCUIT CH302 (WH/BN) FOR A SHORT TO GROUND Key in OFF position. Measure the resistance between ground and PCM C175b-2, circuit CH302 (WH/BN), harness side. Is the resistance greater than 10,000 ohms? YES : Go to B4 . NO : REPAIR circuit CH302 (WH/BN) for a short to ground. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
4. B4 CHECK CIRCUIT CH302 (WH/BN) FOR AN OPEN Measure the resistance between A/C clutch relay socket, circuit CH302 (WH/BN) and PCM C175b-2, circuit CH302 (WH/BN), harness side. Is the resistance less than 5 ohms? YES : Go to B5 . NO : REPAIR circuit 321 (GY/WH) for an open. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
5. B5 CHECK THE PCM CONNECTION Clear the DTCs. Disconnect all the PCM connectors. Check for: corrosion. pushed-out pins. incorrectly seated connector. Connect and correctly seat all the PCM connectors. Operate the system. Does the concern return? YES : INSTALL a new PCM. Refer to «ELECTRONIC ENGINE CONTROLS»(ref-357164) . 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, the evaporator discharge air temperature sensor receives a ground from the HVAC module through circuit RH111 (GY/BU). A 5-volt reference voltage is supplied to the evaporator discharge air temperature sensor from the HVAC module through circuit CH206 (YE/VT).

1. DTC B2826 Front Evaporator Temp Sensor Circuit Failure - The module senses no voltage drop on the sensor reference voltage circuit, indicating an open circuit.
2. DTC B2827 Front Evaporator Temp Sensor Short to Ground - The module senses excessive voltage drop on the sensor reference voltage circuit, indicating a short directly to ground.

This pinpoint test is intended to diagnose the following

1. Wiring, terminals or connectors
2. Evaporator discharge air temperature sensor
3. HVAC module

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1. C1 CHECK THE SENSOR RESISTANCE Key in OFF position. Disconnect: Evaporator Discharge Temperature Sensor C296 Allow enough time for the evaporator to stabilize to the outside ambient temperature. Measure the resistance between evaporator discharge temperature sensor C296 terminals and compare to the table below. Ambient Temperature Resistance -40°C (-40°F) 832,591-1,017,523 ohms -20°C (-4°F) 263,111-290,807 ohms 0°C (32°F) 91,058-100,644 ohms 20°C (68°F) 35,473-39,207 ohms 25°C (77°F) 28,500-31,500 ohms 40°C (104°F) 15,307-16,919 ohms 60°C (140°F) 7,171-7,925 ohms 100°C (212°F) 1,976-2,184 ohms 120°C (248°F) 1,131-1,251 ohms Is the resistance within the specified values for the temperatures? YES : Go to C2 . NO : INSTALL a new evaporator discharge sensor. REFER to «CLIMATE CONTROL»(ref-357171) article. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
2. C2 CHECK THE HVAC SENSOR OUTPUT VOLTAGE Key in ON position. Press the Power button. Measure the voltage between evaporator discharge temperature sensor C296-2, circuit CH206 (YE/VT), harness side and C296-1, circuit RH111 (GY/BU), harness side. Is the voltage between 4.7 and 5.1 volts? YES : INSTALL a new evaporator discharge sensor. REFER to «CLIMATE CONTROL»(ref-357171) article. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation. If code returns, Go to C7 . NO : For DTC B2826 , go to C3 . For DTC B2827 , go to C5 .
3. C3 CHECK CIRCUIT CH206 (YE/VT) FOR AN OPEN Key in OFF position. Disconnect: HVAC Module C2357a Measure the resistance between HVAC module C2357a-6, circuit CH206 (YE/VT), harness side and evaporator discharge temperature sensor C296-2, circuit CH206 (YE/VT), harness side. Is the resistance less than 5 ohms? YES : Go to C4 . NO : REPAIR circuit CH206 (YE/VT) for an open. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
4. C4 CHECK CIRCUIT RH111 (GY/BU) FOR AN OPEN Measure the resistance between HVAC module C2357a-10, circuit RH111 (GY/BU), harness side and evaporator discharge temperature sensor C296-1, circuit RH111 (GY/BU), harness side. Is the resistance less than 5 ohms? YES : Go to C7 . NO : REPAIR circuit RH111 (GY/BU) for an open. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
5. C5 CHECK CIRCUITS CH206 (YE/VT) AND RH111 (GY/BU) FOR A SHORT TOGETHER Key in OFF position. Disconnect: HVAC Module C2357a Measure the resistance between evaporator discharge temperature sensor C296-2, circuit CH206 (YE/VT), harness side and C296-1, circuit RH111 (GY/BU), harness side. Is the resistance greater than 10,000 ohms? YES : Go to C6 . NO : REPAIR circuits CH206 (YE/VT) and RH111 (GY/BU) for a short together. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
6. C6 CHECK CIRCUIT CH206 (YE/VT) FOR A SHORT TO GROUND Measure the resistance between HVAC module C2357a-6, circuit CH206 (YE/VT), harness side and ground. Is the resistance greater than 10,000 ohms? YES : Go to C7 . NO : REPAIR circuit CH206 (YE/VT) for a short to ground. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
7. C7 CHECK THE MODULE CONNECTION Carry out the HVAC Module Cold Boot Process. Refer to «HVAC Module Cold Boot Process»(ref-357136-S25581480002010030800000) . Operate the system. Does the concern return? YES : INSTALL a new HVAC module. REFER to «CLIMATE CONTROL»(ref-357171) article. 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 air inlet (recirc) door actuator motor is supplied voltage or ground on circuit CH208 (GN/OG), depending on desired actuator rotation, by the HVAC module. The HVAC module then supplies the appropriate voltage or ground to the other side of the actuator motor on circuit CH207 (BU/GY).

1. DTC B12A8 Recirc Door Actuator, Drive Circuit(s) Open or Shorted to Ground - The module senses no voltage on the door actuator drive circuit(s), indicating an open circuit or a short directly to ground.
2. DTC B12A9 Recirc Door Actuator, Drive Circuit(s) Shorted to Battery Voltage - The module senses voltage on the door actuator drive circuits, indicating a short directly to voltage.
3. DTC B12AA Recirc Door Actuator, Slow or Door Obstructed - The module senses no change in actuator feedback voltage when the actuator motor has been energized.

This pinpoint test is intended to diagnose the following

1. Wiring, terminals or connectors
2. Air inlet door actuator
3. HVAC module
4. Stuck or damaged linkage or door

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1. E1 CHECK THE HVAC MODULE FOR DTCs Key in ON position. Check the HVAC module for DTCs. Is DTC B12A8 or B12A9 present? YES : For DTC B12A9 , go to E2 . For DTC B12A8 , go to E3 . NO : INSPECT for broken/binding actuator drive shaft or door. REPAIR as necessary. If no condition is found, go to E6 .
2. E2 CHECK CIRCUITS CH207 (BU/GY) AND CH208 (GN/OG) FOR A SHORT TO POWER Key in OFF position. Disconnect: HVAC Module C2357a Disconnect: Recirc Door Actuator C2261 Key in ON position. Measure the voltage between ground and: HVAC module C2357a-16, circuit CH208 (GN/OG), harness side. HVAC module C2357a-15, circuit CH207 (BU/GY), harness side. Is any voltage present? YES : REPAIR circuit CH207 (BU/GY) or CH208 (GN/OG) for a short to power. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation. NO : Go to E5 .
3. E3 CHECK CIRCUITS CH207 (BU/GY) AND CH208 (GN/OG) FOR AN OPEN Key in OFF position. Disconnect: HVAC Module C2357a Disconnect: Recirc Door Actuator C2261 Measure the resistance between HVAC module C2357a-16, circuit CH208 (GN/OG), harness side and recirc door actuator C2261-5, circuit CH208 (GN/OG), harness side. Measure the resistance between HVAC module C2357a-15, circuit CH207 (BU/GY), harness side and recirc door actuator C2261-6, circuit CH207 (BU/GY), harness side. Is the resistance less than 5 ohms? YES : Go to E4 . NO : REPAIR circuit CH207 (BU/GY) or CH208 (GN/OG) for an open. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
4. E4 CHECK CIRCUITS CH207 (BU/GY) AND CH208 (GN/OG) FOR A SHORT TO GROUND Key in OFF position. Disconnect: HVAC Module C2357a Disconnect: Recirc Door Actuator C2261 Measure the resistance between ground and: HVAC module C2357a-16, circuit CH208 (GN/OG), harness side. HVAC module C2357a-15, circuit CH207 (BU/GY), harness side. Is the resistance greater than 10,000 ohms? YES : Go to E5 . NO : REPAIR circuit CH207 (BU/GY) or CH208 (GN/OG) for a short to ground. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
5. E5 CHECK CIRCUITS CH207 (BU/GY) AND CH208 (GN/OG) FOR A SHORT TOGETHER Key in OFF position. Measure the resistance between HVAC module C2357a-15, circuit CH207 (BU/GY), harness side and HVAC module C2357a-16, circuit CH208 (GN/OG), harness side. Is the resistance greater than 10,000 ohms? YES : Go to E6 . NO : REPAIR circuits CH208 (GN/OG) and CH207 (BU/GY) for a short together. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
6. E6 CHECK THE ACTUATOR CONNECTION Disconnect the actuator connector. Check for: corrosion. pushed-out connectors. incorrectly seated connector. Connect and correctly seat the actuator connector. Carry out the HVAC Module Cold Boot Process. Refer to «HVAC Module Cold Boot Process»(ref-357136-S25581480002010030800000) . Operate the system. Does the concern return? YES : CARRY OUT the recirc door actuator component test . Refer to «Defrost/Panel/Floor Door Actuator»(ref-357136-S35407714792010030800000) . If the actuator tests OK, go to E7 . NO : The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. CLEAR the DTCs. TEST the system for normal operation.
7. E7 CHECK THE MODULE CONNECTION Carry out the HVAC Module Cold Boot Process. Refer to «HVAC Module Cold Boot Process»(ref-357136-S25581480002010030800000) . Operate the system. Does the concern return? YES : INSTALL a new HVAC module. REFER to «CLIMATE CONTROL»(ref-357171) article. 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, to rotate the mode door actuator clockwise, the HVAC supplies voltage to the floor/defrost/panel mode door actuator motor through the circuit CH228 (YE/GY), and supplies ground through circuit CH229 (WH/BU). To rotate the mode door actuator counterclockwise, the HVAC module reverses the voltage and ground circuits.

The mode door actuator feedback resistor is supplied a ground from the HVAC module through circuit RH111 (GY/BU) and a 5-volt reference voltage on circuit LH111 (BN/WH). The HVAC module reads the voltage on the mode door actuator feedback circuit VH436 (YE/VT) to determine the mode door actuator position by the position of the actuator feedback resistor wiper arm.

This pinpoint test is intended to diagnose the following

1. Wiring, terminals or connectors
2. Mode door actuator
3. HVAC module
4. Stuck or damaged linkage or door

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1. F1 CHECK THE HVAC MODULE FOR DTCs Key in ON position. Check the HVAC module for DTCs. Are DTCs present? YES : For DTC B12A7 , INSPECT for binding/damaged linkage or door. REPAIR as necessary. If no condition is found, INSTALL a new floor/defrost/panel door actuator. REFER to «CLIMATE CONTROL»(ref-357171) article. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation. For DTC B12A4 , go to F2 . For DTC B298A , go to F3 . For DTC B298B , go to F4 . For DTC B12A5 , go to F6 . For DTC B12A6 , go to F10 . NO : INSPECT for broken actuator drive shaft, cam or door. REPAIR as necessary. If no condition is found, go to F13 .
2. F2 CHECK THE ACTUATOR MOTOR DRIVE CIRCUITS FOR A SHORT TO POWER Key in OFF position. Disconnect: HVAC Module C2357a Disconnect: Floor/Defrost/Panel Door Actuator C2278 Key in ON position. Measure the voltage between ground and: HVAC module C2357a-19, circuit CH228 (YE/GY), harness side. HVAC module C2357a-20, circuit CH229 (WH/BU), harness side. Is any voltage present? YES : REPAIR the circuit CH228 (YE/GY) or CH229 (WH/BU) for a short to power. TEST the system for normal operation. NO : Go to F5 .
3. F3 CHECK THE ACTUATOR MOTOR DRIVE CIRCUITS FOR AN OPEN Key in OFF position. Disconnect: HVAC Module C2357a Disconnect: Floor/Defrost/Panel Door Actuator C2278 Measure the resistance between HVAC module C2357a-19, circuit CH228 (YE/GY), harness side and floor/defrost/panel door actuator C2278-6, circuit CH228 (YE/GY), harness side. Measure the resistance between HVAC module C2357a-20, circuit CH229 (WH/BU), harness side and floor/defrost/panel door actuator C2278-5, circuit CH229 (WH/BU). Are the resistances less than 5 ohms? YES : Go to F13 . NO : REPAIR the circuit CH228 (YE/GY) or CH229 (WH/BU) for an open. TEST the system for normal operation.
4. F4 CHECK THE ACTUATOR MOTOR DRIVE CIRCUITS FOR A SHORT TO GROUND Key in OFF position. Disconnect: HVAC Module C2357a Disconnect: Floor/Defrost/Panel Door Actuator C2278 Measure the resistance between ground and: HVAC module C2357a-19, circuit CH228 (YE/GY), harness side. HVAC module C2357a-20, circuit CH229 (WH/BU), harness side. Are the resistances greater than 10,000 ohms? YES : Go to F5 . NO : REPAIR the circuit CH228 (YE/GY) or CH229 (WH/BU) for a short to ground. TEST the system for normal operation.
5. F5 CHECK THE ACTUATOR MOTOR DRIVE CIRCUITS FOR A SHORT TOGETHER Key in OFF position. Measure the resistance between HVAC module C2357a-19, circuit CH228 (YE/GY), harness side and HVAC module C2357a-20, circuit CH229 (WH/BU), harness side. Is the resistance greater than 10,000 ohms? YES : Go to F13 . NO : REPAIR circuits CH228 (YE/GY) and CH229 (WH/BU) for a short together. TEST the system for normal operation.
6. F6 CHECK CIRCUIT VH436 (YE/VT) FOR AN OPEN Key in OFF position. Disconnect: HVAC Module C2357a Disconnect: Floor/Defrost/Panel Door Actuator C2278 Measure the resistance between HVAC module C2357a-8, circuit VH436 (YE/VT), harness side and floor/defrost/panel door actuator C2278-2, circuit VH436 (YE/VT), harness side. Is the resistance less than 5 ohms? YES : CARRY OUT the Defrost/Panel/Floor Door actuator component test . Refer to «Defrost/Panel/Floor Door Actuator»(ref-357136-S35407714792010030800000) . If the actuator tests OK, go to F7 . NO : REPAIR circuit VH436 (YE/VT) for an open. TEST the system for normal operation.
7. F7 CHECK CIRCUIT VH436 (YE/VT) FOR A SHORT TO POWER Key in ON position. Measure the voltage between ground and HVAC module C2357a-8, circuit VH436 (YE/VT), harness side. Is any voltage present? YES : REPAIR circuit VH436 (YE/VT) for a short to power. TEST the system for normal operation. NO : Go to F8 .
8. F8 CHECK CIRCUITS LH111 (BN/WH) AND VH436 (YE/VT) FOR A SHORT TOGETHER Key in OFF position. Measure the resistance between HVAC module C2357a-11, circuit LH111 (BN/WH), harness side and HVAC module C2357a-8, circuit VH436 (YE/VT), harness side. Is the resistance greater than 10,000 ohms? YES : Go to F9 . NO : REPAIR circuits LH111 (BN/WH) and VH436 (YE/VT) for a short together. TEST the system for normal operation.
9. F9 CHECK THE ACTUATOR RETURN CIRCUIT RH111 (GY/BU) FOR AN OPEN Measure the resistance between HVAC module C2357a-10, circuit RH111 (GY/BU), harness side and floor/defrost/panel door actuator C2278-1, circuit RH111 (GY/BU), harness side. Is the resistance less than 5 ohms? YES : Go to F13 . NO : REPAIR circuit RH111 (GY/BU) for an open. TEST the system for normal operation.
10. F10 CHECK CIRCUIT VH436 (YE/VT) FOR A SHORT TO GROUND Key in OFF position. Disconnect: HVAC Module C2357a Disconnect: Floor/Defrost/Panel Door Actuator C2278 Measure the resistance between ground and HVAC module C2357a-8, circuit VH436 (YE/VT), harness side. Are the resistances greater than 10,000 ohms? YES : Go to F11 . NO : REPAIR circuit VH436 (YE/VT) for a short to ground. TEST the system for normal operation.
11. F11 CHECK CIRCUITS RH111 (GY/BU) AND VH436 (YE/VT) FOR A SHORT TOGETHER Measure the resistance between HVAC module C2357a-10, circuit RH111 (GY/BU), harness side and HVAC module C2357a-8, circuit VH436 (YE/VT), harness side. Is the resistance greater than 10,000 ohms? YES : Go to F12 . NO : REPAIR circuits RH111 (GY/BU) and VH436 (YE/VT) for a short together. TEST the system for normal operation.
12. F12 CHECK CIRCUIT LH111 (BN/WH) FOR AN OPEN Measure the resistance between HVAC module C2357a-11, circuit LH111 (BN/WH), harness side and floor/defrost/panel door actuator C2278-3, circuit LH111 (BN/WH), harness side. Is the resistance less than 5 ohms? YES : Go to F13 . NO : REPAIR circuit LH111 (BN/WH) for an open. TEST the system for normal operation.
13. F13 CHECK THE ACTUATOR CONNECTION Disconnect the actuator connector. Check for: corrosion. pushed-out connectors. incorrectly seated connector. Connect and correctly seat the actuator connector. Carry out the HVAC Module Cold Boot Process. Refer to «HVAC Module Cold Boot Process»(ref-357136-S25581480002010030800000) . Operate the system. Does the concern return? YES : CARRY OUT the Floor/Defrost/Panel Door Actuator component test . Refer to «Defrost/Panel/Floor Door Actuator»(ref-357136-S35407714792010030800000) . If the actuator tests OK, go to F14 . NO : The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. CLEAR the DTCs. TEST the system for normal operation.
14. F14 CHECK THE MODULE CONNECTION Carry out the HVAC Module Cold Boot Process. Refer to «HVAC Module Cold Boot Process»(ref-357136-S25581480002010030800000) . Operate the system. Does the concern return? YES : INSTALL a new HVAC module. REFER to «CLIMATE CONTROL»(ref-357171) article. 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, warm coolant flows from the engine through the heater core and back to the engine.

This pinpoint test is intended to diagnose the following

1. Plugged heater core
2. Coolant level
3. Temperature blend door

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1. G1 CHECK FOR CORRECT ENGINE COOLANT LEVEL Key in OFF position. Check the engine coolant level. Is the engine coolant at the correct level as indicated on the engine coolant recovery reservoir? YES : Go to G3 . NO : Go to G2 .
2. G2 CHECK THE ENGINE COOLING SYSTEM FOR LEAKS Pressure test the cooling system for leaks. Refer to «ENGINE COOLING»(ref-357157) article. Does the engine cooling system leak? YES : REPAIR the engine coolant leak. TEST the system for normal operation. NO : Go to G3 .
3. G3 CHECK FOR COOLANT FLOW TO THE HEATER CORE Run the engine until it reaches normal operation temperature. Select the FLOOR position on the control assembly. Set the temperature control to full warm and the blower to the lowest setting. Using a suitable temperature measuring device, check the heater core inlet hose to see if it is hot. Is the heater core inlet hose temperature above 65.5°C (150°F)? YES : Go to G4 . NO : REFER to «ENGINE COOLING»(ref-357157) article to diagnose the engine not reaching normal operating temperature.
4. G4 CHECK FOR A PLUGGED OR RESTRICTED HEATER CORE Using a suitable temperature measuring device, measure the heater core outlet hose temperature. Is the heater core outlet hose temperature similar to the inlet hose temperature (within approximately 6-17°C [10-30°F])? YES : Go to «Pinpoint Test G»(ref-357136-S27607800012010030800000) and DIAGNOSE for a blend door actuator. NO : INSTALL a new heater core. REFER to «CLIMATE CONTROL»(ref-357171) article. TEST the system for normal operation.

Under normal operation, when A/C is requested a message is sent over the Medium Speed Controller Area Network (MS-CAN) bus to the instrument cluster, then from the instrument cluster through the High Speed Controller Area Network (HS-CAN) bus to the PCM. Battery voltage for the A/C clutch relay contacts is provided through circuit SBB13 (GY/RD). When the PCM receives the request, the A/C pressure transducer does not indicate excessive pressure and the evaporator temperature sensor does not indicate a low evaporator temperature, it energizes the relay sending battery voltage to the A/C clutch through circuit CH401 (VT/WH). Ground is supplied for the A/C clutch through circuit GD120 (BK/GN).

This pinpoint test is intended to diagnose the following

1. Fuse
2. Wiring, terminals or connectors
3. PCM
4. HVAC module
5. A/C evaporator discharge temperature sensor
6. A/C pressure transducer
7. A/C compressor clutch field coil
8. A/C control relay
9. A/C clutch air gap

Under normal operation, when A/C is requested a message is sent over the Medium Speed Controller Area Network (MS-CAN) bus to the instrument cluster, then from the instrument cluster through the High Speed Controller Area Network (HS-CAN) bus to the PCM. Battery voltage for the A/C clutch relay contacts is provided through circuit SBB13 (GY/RD). When the PCM receives the request, the A/C pressure transducer does not indicate excessive pressure and the evaporator temperature sensor does not indicate a low evaporator temperature, it energizes the relay sending battery voltage to the A/C clutch through circuit CH401 (VT/WH). Ground is supplied for the A/C clutch through circuit GD120 (BK/GN).

This pinpoint test is intended to diagnose the following

1. Wiring, terminals or connectors
2. PCM
3. HVAC module
4. A/C evaporator discharge temperature sensor
5. A/C pressure transducer
6. A/C control relay
7. A/C clutch air gap

Under normal operation, when A/C is requested a message is sent over the Medium Speed Controller Area Network (MS-CAN) bus to the instrument cluster, then from the instrument cluster through the High Speed Controller Area Network (HS-CAN) bus to the PCM. Battery voltage for the A/C clutch relay contacts is provided through circuit SBB13 (GY/RD). When the PCM receives the request, the A/C pressure transducer does not indicate excessive pressure and the evaporator temperature sensor does not indicate a low evaporator temperature, it energizes the relay sending battery voltage to the A/C clutch through circuit CH401 (VT/WH). Ground is supplied for the A/C clutch through circuit GD120 (BK/GN).

This pinpoint test is intended to diagnose the following

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

Under normal operation, to rotate the blend door actuator clockwise, the HVAC module supplies voltage to the blend door actuator motor through circuit CH233 (VT/BN), and supplies ground through circuit CH234 (YE/GN). To rotate the blend door actuator counterclockwise, the HVAC module reverses the voltage and ground circuits.

The blend door actuator feedback resistors are supplied a ground from the HVAC module by circuit RH111 (GY/BU) and a 5-volt reference voltage on circuit LH111 (BN/WH). The HVAC module reads the voltage on circuit VH439 (GY/VT) to determine the blend door actuator position by the position of the actuator feedback resistor wiper arm.

This pinpoint test is intended to diagnose the following

1. Wiring, terminals or connectors
2. Blend door actuator
3. HVAC module
4. Stuck or damaged linkage or door

Scheme 30

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Scheme 33

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Scheme 35

Scheme 36

Scheme 37

Scheme 38

Scheme 39

1. K1 CHECK THE HVAC MODULE FOR DTCs Key in ON position. Check the HVAC module for DTCs. Are any DTCs present? YES : For DTC B12B7 , INSPECT for binding/damaged linkage or door. REPAIR as necessary. If no condition is found, INSTALL a new door actuator. REFER to «CLIMATE CONTROL»(ref-357171) article. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation. For DTC B12B3 , go to K2 . For DTC B297A , go to K3 . For DTC B297B , go to K4 . For DTC B12B5 , go to K6 . For DTC B12B6 , go to K10 . NO : CHECK that the A/C system pressure is above 290 kPa (42 psi). If the pressure is below 290 kPa (42 psi), REFER to «Fluorescent Dye Leak Detection»(ref-357136-S21353745912010030800000) . INSPECT for broken/binding actuator drive shaft or door. If no condition is found, go to K13 .
2. K2 CHECK THE ACTUATOR MOTOR DRIVE CIRCUITS FOR A SHORT TO POWER Key in OFF position. Disconnect: HVAC Module C2357a Disconnect: Blend Door Actuator C289 Key in ON position. Measure the voltage between ground and: HVAC module C2357a-21, circuit CH233 (VT/BN), harness side. HVAC module C2357a-22, circuit CH234 (YE/GN), harness side. Is any voltage present? YES : REPAIR the circuit(s) for a short to power. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation. NO : Go to K5 .
3. K3 CHECK THE ACTUATOR MOTOR DRIVE CIRCUITS FOR AN OPEN Key in OFF position. Disconnect: HVAC Module C2357a Disconnect: Blend Door Actuator C289 Measure the resistance between HVAC module C2357a-21, circuit CH233 (VT/BN), harness side and LH blend door actuator C289-6, circuit CH233 (VT/BN), harness side. Measure the resistance between HVAC module C2357a-22, circuit CH234 (YE/GN), harness side and LH blend door actuator C289-5, circuit CH234 (YE/GN), harness side. Are the resistances less than 5 ohms? YES : Go to K13 . NO : REPAIR the circuit(s) for an open. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
4. K4 CHECK THE ACTUATOR MOTOR DRIVE CIRCUITS FOR A SHORT TO GROUND Key in OFF position. Disconnect: HVAC Module C2357a Disconnect: Blend Door Actuator C289 Measure the resistance between ground and: HVAC module C2357a-21, circuit CH233 (VT/BN), harness side. HVAC module C2357a-22, circuit CH234 (YE/GN), harness side. Are the resistances greater than 10,000 ohms? YES : Go to K5 . NO : REPAIR the circuit(s) for a short to ground. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
5. K5 CHECK THE ACTUATOR MOTOR DRIVE CIRCUITS FOR A SHORT TOGETHER Key in OFF position. Measure the resistance between HVAC module C2357a-22, circuit CH234 (YE/GN), harness side and HVAC module C2357a-21, circuit CH233 (VT/BN), harness side. Is the resistance greater than 10,000 ohms? YES : Go to K13 . NO : REPAIR circuit(s) for a short together. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
6. K6 CHECK CIRCUIT VH439 (GY/VT) FOR AN OPEN Key in OFF position. Disconnect: HVAC Module C2357a Disconnect: Blend Door Actuator C289 Measure the resistance between HVAC module C2357a-7, circuit VH439 (GY/VT), harness side and blend door actuator C289-2, circuit VH439 (GY/VT), harness side. Is the resistance less than 5 ohms? YES : Go to K7 . NO : REPAIR circuit VH439 (GY/VT) for an open. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
7. K7 CHECK CIRCUIT VH439 (GY/VT) FOR A SHORT TO POWER Key in ON position. Measure the voltage between ground and HVAC module C2357a-7, circuit VH439 (GY/VT), harness side. Is any voltage present? YES : REPAIR circuits VH439 (GY/VT) for a short to power. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation. NO : Go to K8 .
8. K8 CHECK CIRCUITS LH111 (BN/WH) AND VH439 (GY/VT) FOR A SHORT TOGETHER Key in OFF position. Measure the resistance between HVAC module C2357a-11, circuit LH111 (BN/WH) and HVAC module C2357a-7, circuit VH439 (GY/VT), harness side. Is the resistance greater than 10,000 ohms? YES : Go to K9 . NO : REPAIR circuits LH111 (BN/WH) and VH439 (GY/VT) for a short together. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
9. K9 CHECK THE ACTUATOR RETURN CIRCUIT RH111 (GY/BU) FOR AN OPEN Measure the resistance between HVAC module C2357a-10, circuit RH111 (GY/BU) and blend door actuator C289-1, circuit RH111 (GY/BU), harness side. Is the resistance less than 5 ohms? YES : Go to K13 . NO : REPAIR circuit RH111 (GY/BU) for an open. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
10. K10 CHECK CIRCUIT VH439 (GY/VT) FOR A SHORT TO GROUND Key in OFF position. Disconnect: HVAC Module C2357a Disconnect: Blend Door Actuator C289 Measure the resistance between ground and HVAC module C2357a-7, circuit VH439 (GY/VT), harness side. Is the resistance greater than 10,000 ohms? YES : Go to K11 . NO : REPAIR circuit VH439 (GY/VT) for a short to ground. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
11. K11 CHECK CIRCUITS RH111 (GY/BU) AND VH439 (GY/VT) FOR A SHORT TOGETHER Measure the resistance between HVAC module C2357a-10, circuit RH111 (GY/BU) and HVAC module C2357a-7, circuit VH439 (GY/VT), harness side. Is the resistance greater than 10,000 ohms? YES : Go to K12 . NO : REPAIR circuits RH111 (GY/BU) and VH439 (GY/VT) for a short together. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
12. K12 CHECK CIRCUIT LH111 (BN/WH) FOR AN OPEN Measure the resistance between HVAC module C2357a-11, circuit LH111 (BN/WH) and blend door actuator C289-3, circuit LH111 (BN/WH), harness side. Is the resistance less than 5 ohms? YES : Go to K13 . NO : REPAIR circuit LH111 (BN/WH) for an open. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
13. K13 CHECK THE ACTUATOR CONNECTION Clear the DTCs. Disconnect the actuator connector. Check for: corrosion. pushed-out connectors. incorrectly seated connector. Connect and correctly seat the actuator connector. Carry out the HVAC Module Cold Boot Process. Refer to «HVAC Module Cold Boot Process»(ref-357136-S25581480002010030800000) . Operate the system. Does the concern return? YES : CARRY OUT the blend door actuator component test . Refer to «Blend Door Actuator»(ref-357136-S06198323102010030800000) . If the actuator tests OK, go to K14 . NO : The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. CLEAR the DTCs. TEST the system for normal operation.
14. K14 CHECK THE MODULE CONNECTION Carry out the HVAC Module Cold Boot Process. Refer to «HVAC Module Cold Boot Process»(ref-357136-S25581480002010030800000) . Operate the system. Does the concern return? YES : INSTALL a new HVAC module. REFER to «CLIMATE CONTROL»(ref-357171) article. 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 relay coil receives ignition voltage through circuit CDC33 (VT/GN). The coil receives ground from the HVAC module through circuit CH123 (VT/GN) if any function selector position but OFF is selected. Voltage is supplied to the relay switch contact through circuit SBB12 (GN/RD). When the relay coil is energized, voltage is delivered to the blower motor through circuit CH402 (YE/GN). Ground for the blower motor is provided through circuit VH301 (YE/BU) from the blower resistor or the blower switch (HI). The blower resistor and blower switch is grounded through circuit GD138 (BK/WH).

1. DTC B12AF Front Blower Motor Relay Drive Circuit Shorted to Battery Voltage - The module senses voltage on the relay coil ground circuit, indicating a short directly to voltage.
2. DTC B12B0 Front Blower Motor Relay Drive Circuit Open or Shorted to Ground - The module senses no voltage on the relay coil ground circuit, indicating an open or a short directly to ground.

This pinpoint test is intended to diagnose the following

1. Fuse(s)
2. Wiring, terminals or connectors
3. Blower motor
4. Blower motor relay
5. Blower motor switch
6. HVAC module

Scheme 40

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Scheme 43

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Scheme 45

Scheme 46

1. L1 CHECK THE HVAC MODULE FOR DTCs Key in ON position. Check the HVAC module for DTCs. Are any DTCs present? YES : For DTC B12AF , REPAIR circuit CH123 (VT/GN) for a short to voltage. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation. For DTC B12B0 , CARRY OUT the blower motor relay component test. Refer to appropriate COMPONENT TESTING article. If the relay tests OK, go to L2 . NO : Go to L3 .
2. L2 CHECK THE RELAY COIL SUPPLY VOLTAGE Key in OFF position. Disconnect: Blower Motor Relay Key in ON position. Measure the voltage between blower motor relay socket pin 1, circuit CDC33 (VT/GN) and ground. Is the voltage greater than 10 volts? YES : REPAIR circuit CH123 (VT/GN) for an open. TEST the system for normal operation. NO : REPAIR circuit CDC33 (VT/GN) for an open. TEST the system for normal operation.
3. L3 CHECK CIRCUIT VH301 (YE/BU) FOR GROUND Key in OFF position. Disconnect: Blower Motor C2004 Turn the function selector switch to the PANEL position. Turn the blower motor switch to the HI position. Measure the resistance between blower motor connector C2004-1, circuit VH301 (YE/BU), harness side and ground. Is the resistance less than 5 ohms? YES : Go to L6 . NO : Go to L4 .
4. L4 CHECK CIRCUIT VH301 (YE/BU) FOR AN OPEN Disconnect: Blower Motor Switch C2357b Measure the resistance between blower motor switch C2357b-2, circuit VH301 (YE/BU), harness side and blower motor C2004-1, circuit VH301 (YE/BU), harness side. Is the resistance less than 5 ohms? YES : Go to L5 . NO : REPAIR circuit VH301 (YE/BU) for an open. TEST the system for normal operation.
5. L5 CHECK CIRCUIT GD138 (BK/WH) FOR AN OPEN Measure the resistance between blower motor switch C2357b-1, circuit GD138 (BK/WH), harness side and ground. Is the resistance less than 5 ohms? YES : INSTALL a new blower motor switch. REFER to «CLIMATE CONTROL»(ref-357171) article. TEST the system for normal operation. NO : REPAIR circuit GD138 (BK/WH) for an open. TEST the system for normal operation.
6. L6 CHECK A/C BLOWER MOTOR CIRCUIT CH402 (YE/GN) FOR VOLTAGE Key in ON position. Measure the voltage between blower motor C2004-2, circuit CH402 (YE/GN), harness side and ground. Is the voltage greater than 10 volts? YES : INSTALL a new blower motor. REFER to «CLIMATE CONTROL»(ref-357171) article. TEST the system for normal operation. NO : Go to L7 .
7. L7 CHECK CIRCUIT CH402 (YE/GN) FOR AN OPEN Key in OFF position. Disconnect: Blower Motor Relay Measure the resistance between blower motor relay connector pin 5, circuit CH402 (YE/GN) and blower motor C2004-2, circuit CH402 (YE/GN), harness side. Is the resistance less than 5 ohms? YES : Go to L8 . NO : REPAIR circuit CH402 (YE/GN) for an open. TEST the system for normal operation.
8. L8 CHECK THE BLOWER MOTOR RELAY Connect: Blower Motor C2004 Key in ON position. Connect a fused jumper lead between blower motor relay socket pin 3, circuit SBB12 (GN/RD) and pin 5, circuit CH402 (YE/GN). Does the blower motor operate? YES : CARRY OUT the blower motor relay component test. Refer to appropriate COMPONENT TESTING article. If the relay tests OK, go to L9 . NO : VERIFY Battery Junction Box (BJB) fuse 12 (40A) is OK. If OK, REPAIR circuit SBB12 (GN/RD) for an open. TEST the system for normal operation.
9. L9 CHECK THE MODULE CONNECTION Carry out the HVAC Module Cold Boot Process. Refer to «HVAC Module Cold Boot Process»(ref-357136-S25581480002010030800000) . Operate the system. Does the concern return? YES : INSTALL a new HVAC module. REFER to «CLIMATE CONTROL»(ref-357171) article. 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.

Under normal operation, the blower motor is provided ground from the blower resistor through circuit VH301 (YE/BU). The resistor gets a ground from circuit GD138 (BK/WH) in the lowest blower setting. In MED-LO and MED-HI the resistor gets ground from the blower motor switch through circuit CH428 (GN/WH) or CH429 (GY/BN), depending on selected speed. In HI, the blower motor is grounded directly through the blower motor switch from circuit VH301 (YE/BU) to circuit GD138 (BK/WH). The blower switch receives its ground from circuit GD138 (BK/WH).

This pinpoint test is intended to diagnose the following

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

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Scheme 51

1. M1 CHECK THE BLOWER MOTOR OPERATION Key in ON position. 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 does not operate in HI, go to M2 . If the blower motor does not operate in MED-HI, go to M3 . If the blower motor does not operate in MED-LO, go to M4 . If the blower motor does not operate in LO, go to M5 . For all other symptoms, go to M7 . NO : Go to «Pinpoint Test L»(ref-357136-S16105134192010030800000) .
2. M2 CHECK CIRCUIT VH301 (YE/BU) FOR AN OPEN Key in OFF position. Disconnect: Blower Motor Switch C2357b Disconnect: Blower Motor C2004 Measure the resistance between blower motor switch C2357b-2, circuit VH301 (YE/BU), harness side and blower motor C2004-1, circuit VH301 (YE/BU), harness side. Is the resistance less than 5 ohms? YES : Go to M6 . NO : REPAIR circuit VH301 (YE/BU) for an open. TEST the system for normal operation.
3. M3 CHECK CIRCUIT CH429 (GY/BN) FOR AN OPEN Key in OFF position. Disconnect: Blower Motor Switch C2357b Disconnect: Blower Motor Resistor C293 Measure the resistance between blower motor switch C2357b-3, circuit CH429 (GY/BN), harness side and blower motor resistor C293-2, circuit CH429 (GY/BN), harness side. Is the resistance less than 5 ohms? YES : Go to M6 . NO : REPAIR circuit CH429 (GY/BN) for an open. TEST the system for normal operation.
4. M4 CHECK CIRCUIT CH428 (GN/WH) FOR AN OPEN Key in OFF position. Disconnect: Blower Motor Switch C2357b Disconnect: Blower Motor Resistor C293 Measure the resistance between blower motor switch C2357b-4, circuit CH428 (GN/WH), harness side and blower motor resistor C293-1, circuit CH428 (GN/WH), harness side. Is the resistance less than 5 ohms? YES : Go to M6 . NO : REPAIR circuit CH428 (GN/WH) for an open. TEST the system for normal operation.
5. M5 CHECK BLOWER MOTOR RESISTOR GROUND CIRCUIT GD138 (BK/WH) FOR AN OPEN Measure the resistance between blower motor resistor C293-3, circuit GD138 (BK/WH), harness side and ground. Is the resistance less than 5 ohms? YES : Go to M6 . NO : REPAIR circuit GD138 (BK/WH) for an open. TEST the system for normal operation.
6. M6 CHECK THE BLOWER MOTOR RESISTOR Carry out the blower motor resistor component test . Refer to «Resistor - Blower Motor»(ref-357136-S35467832312010030800000) . Does the blower motor resistor test good? YES : Go to M7 . NO : INSTALL a new blower motor resistor. REFER to «CLIMATE CONTROL»(ref-357171) article. TEST the system for normal operation.
7. M7 CHECK THE BLOWER MOTOR SWITCH CIRCUIT GD138 (BK/WH) FOR AN OPEN Measure the resistance between blower motor switch C2357b-1, circuit GD138 (BK/WH), harness side and ground. Is the resistance less than 5 ohms? YES : Go to M8 . NO : REPAIR circuit GD138 (BK/WH) for an open. TEST the system for normal operation.
8. M8 CHECK CIRCUITS VH301 (YE/BU), CH428 (GN/WH) AND CH429 (GY/BN) FOR A SHORT TO GROUND Key in OFF position. Disconnect: Blower Motor C2004 Disconnect: Blower Motor Resistor C293 Place the blower switch in the lowest setting. Measure the resistance between ground and blower motor resistor: C293-1, circuit CH428 (GN/WH), harness side. C293-2, circuit CH429 (GY/BN), harness side. C293-4, circuit VH301 (YE/BU), harness side. Are the resistances greater than 10,000 ohms? YES : Go to M9 . NO : REPAIR the affected circuit for a short to ground. TEST the system for normal operation.
9. M9 CHECK THE BLOWER MOTOR CIRCUITS FOR SHORTS TOGETHER Measure the resistance between blower motor resistor: C293-1, circuit CH428 (GN/WH), harness side and C293-4, circuit VH301 (YE/BU), harness side. C293-1, circuit CH428 (GN/WH), harness side and C293-2, circuit CH429 (GY/BN), harness side. C293-4, circuit VH301 (YE/BU), harness side and C293-2, circuit CH429 (GY/BN), harness side. Are the resistances greater than 10,000 ohms? YES : INSTALL a new blower motor switch. REFER to «CLIMATE CONTROL»(ref-357171) article. TEST the system for normal operation. NO : REPAIR the affected circuits. TEST the system for normal operation.

Under normal operation, the HVAC receives ground through circuit GD138 (BK/WH). The HVAC module is supplied constant battery voltage through circuit SBP15 (WH/RD) and ignition switched voltage through circuit CBP37 (WH).

1. DTC B1676 Battery Voltage Out of Range - The module senses when voltage is less than 9 volts or greater than 16 volts.

This pinpoint test is intended to diagnose the following

1. Fuse(s)
2. Wiring, terminals or connectors
3. HVAC module

Scheme 52

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Scheme 54

1. N1 RETRIEVE ALL Continuous Memory Diagnostic Trouble Codes (CMDTCs) IN ALL MODULES Enter the following diagnostic mode on the diagnostic tool: Self Test - All CMDTCs Is B1317, B1318 or B1676 present in more than one module AND P0563, P0620, P0625, P0626 or P065B present in the PCM? YES : REFER to «CHARGING SYSTEM - GENERAL INFORMATION»(ref-357135) article for diagnosis of the battery and charging system. CLEAR all CMDTCs. TEST the system for normal operation. NO : Go to N2 .
2. N2 CHECK BATTERY CONDITION Refer to «BATTERY, MOUNTING AND CABLES»(ref-357167) article 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 - GENERAL INFORMATION»(ref-357135) article to diagnose the charging system. CLEAR all CMDTCs. TEST the system for normal operation. If the battery passed the condition test and did not require a recharge, go to N3 . NO : INSTALL a new battery. CLEAR all CMDTCs. TEST the system for normal operation.
3. N3 CHECK CHARGING SYSTEM VOLTAGE NOTE: Do not allow the engine speed to increase above 2,000 RPM while performing this step or the generator may self excite and result in default charging system output voltage. If engine speed goes above 2,000 RPM, shut the vehicle OFF and restart the engine before performing this step. Measure the voltage of the battery with and without a load on the charging system as follows: Turn off all accessories and run the engine at 1,500 RPM for a minimum of 2 minutes while measuring battery voltage. Turn on headlights and HVAC fan on high and run engine at 1,500 RPM for a minimum of 2 minutes while measuring battery voltage. Are the voltages between 13 and 15.2 volts? YES : Go to N4 . NO : REFER to «CHARGING SYSTEM - GENERAL INFORMATION»(ref-357135) article to diagnose the charging system. CLEAR all CMDTCs. TEST the system for normal operation.
4. N4 CHECK FOR VOLTAGE MONITORING THE MODULE SUPPLY VOLTAGE (VBAT_CC) HVAC PID Key in ON position. Enter the following diagnostic mode on the diagnostic tool: VBAT_CC HVAC PID Monitor the battery voltage VBAT_CC HVAC PID. Is the battery voltage less than 9 or greater than 15.5 volts? YES : If voltage is less than 9 volts, go to N5 . If voltage is greater than 15.5 volts, INSTALL a new HVAC module. REFER to «CLIMATE CONTROL»(ref-357171) article. CLEAR all CMDTCs. REPEAT the self-test. NO : Go to N7 .
5. N5 CHECK CIRCUIT GD138 (BK/WH) FOR EXCESSIVE RESISTANCE Key in OFF position. Disconnect: HVAC C2357a Measure the resistance between HVAC C2357a-23, circuit GD138 (BK/WH), harness side and ground. Is the resistance less than 1 ohm? YES : Go to N6 . NO : REPAIR circuit GD138 (BK/WH) for an open. TEST the system for normal operation.
6. N6 CHECK CIRCUITS SBP15 (WH/RD) AND CBP37 (WH) FOR AN OPEN Key in ON position. With the engine running, measure the voltage between ground and: HVAC module C2357a-13, circuit SBP15 (WH/RD), harness side. HVAC module C2357a-12, circuit CBP37 (WH), harness side. Is the voltage greater than 10 volts and less than 16 volts? YES : Go to N7 . NO : If DTC B1676 is present in multiple modules, REFER to «CHARGING SYSTEM - GENERAL INFORMATION»(ref-357135) article. If DTC B1676 is present only in the HVAC module, VERIFY Smart Junction Box (SJB) fuse 15 (10A) and fuse 37 (10A) is OK. If OK, REPAIR circuit SBP15 (WH/RD) or CBP37 (WH) for an open. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
7. N7 CHECK THE MODULE CONNECTION Carry out the HVAC Module Cold Boot Process. Refer to «HVAC Module Cold Boot Process»(ref-357136-S25581480002010030800000) . Operate the system. Does the concern return? YES : INSTALL a new HVAC module. REFER to «CLIMATE CONTROL»(ref-357171) article. 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.

Scheme 55

Scheme 56

Refrigerant Identification Testing

SPECIAL TOOLS - REFRIGERANT IDENTIFICATION TESTING Illustration Tool Name Tool Number Refrigerant Identifier with Air-Radiator 198-00003 or equivalent

Refrigerant Identification

1. Follow the instructions included with the Refrigerant Identifier with Air-Radiator to obtain the sample for testing.
2. The Refrigerant Identifier with Air-Radiator 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 scan tool 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 scan tool 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, the scan tool 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.