Honda CR-V: A/C Signal Circuit Troubleshooting

NOTE:

1. Turn the ignition switch ON (II).

2. Check if the blower motor operates at all speeds.

Does the blower motor operate at all speeds? YES-Go to step 3.

NO-Repair the problem in the blower motor circuit. 3. Turn the ignition switch OFF.

4. Disconnect the HVAC control unit 28P connector.

5. Turn the ignition switch ON (II).

6. Measure the voltage between the HVAC control unit 28P connector terminal No. 10 and body ground.

Honda CR-V. HVAC (Heating, Ventilation, and Air Conditioning)

Is there voltage? YES-Go to step 13.

NO-Go to step 7.

7. Turn the ignition switch OFF.

8. Disconnect the A/C compressor clutch 3P connector.

9. Turn the ignition switch ON (II).

10. Measure the voltage between the A/C compressor clutch 3P connector terminal No.1 and body ground.

Honda CR-V. HVAC (Heating, Ventilation, and Air Conditioning)

Is there battery voltage? YES-Go to step 11.

NO-Repair open in the wire between the A/C compressor and the MICU. If the wire is OK, substitute a known-good MICU and recheck. If the symptom goes away, replace the original MICU.

11. Test the A/C compressor thermal protector.

Is the A/C compressor thermal protector OK? YES-Go to step 12.

NO-Replace the A/C compressor thermal protector.

12. Check for continuity between the HVAC control unit 28P connector terminal No. 10 and the A/C compressor clutch 3P connector terminal No.2.

Honda CR-V. HVAC (Heating, Ventilation, and Air Conditioning)

Is there continuity? YES-Check for loose wires or poor connections at the HVAC control unit 28P connector and at the A/C compressor clutch 3P connector.

NO-Repair open in the wire between the HVAC control unit and A/C compressor.

13. Turn the ignition switch OFF.

14. Measure the evaporator temperature sensor resistance between the HVAC control unit 28P connector terminals No. 9 and No. 19.

Honda CR-V. HVAC (Heating, Ventilation, and Air Conditioning)

Is resistance less than 24 k Ω ? YES-Check for loose wires or poor connections at the HVAC control unit 28P connector. If the connections are good, substitute a known-good HVAC control unit and recheck. If the symptom goes away, replace the original HVAC control unit.

NO-Test the evaporator temperature sensor.

Evaporator Temperature Sensor Test

1. Remove the evaporator core and the evaporator temperature sensor.

2. Dip the sensor in ice water, and measure the resistance between its terminals.

Honda CR-V. HVAC (Heating, Ventilation, and Air Conditioning)

3. Then pour warm water on the sensor, and check for a change in resistance.

4. Compare the resistance readings with the specifications shown in the graph; the resistance should be within the specifications.

Honda CR-V. HVAC (Heating, Ventilation, and Air Conditioning)

5. If the resistance is not as specified, replace the evaporator temperature sensor.

Power Transistor Test

1. Remove the passenger's dashboard undercover.

2. Disconnect the 4P connector from the power transistor.

3. Measure the resistance between the No.3 and No.4 terminals of the power transistor. It should be about 1.5 k Ω.

NOTE: Also check the blower motor. Power transistor failuer can be caused by a defective blower motor.

Honda CR-V. HVAC (Heating, Ventilation, and Air Conditioning)

4. Carefully release the lock tab on the No.1 terminal (RED) (A) in the 4P connector, then remove the terminal and insulate it from body ground.

Honda CR-V. HVAC (Heating, Ventilation, and Air Conditioning)

5. Reconnect the 4P connector to the power transistor.

6. Make sure the RED wire is completely isolated, then supply 12 V to the No. 1 cavity with a jumper wire.

7. Turn the ignition switch ON (II), and check that the blower motor runs.

Air Mix Control Motor Test

NOTE: Before testing, check for HVAC DTCs.

1. Disconnect the 7P connector from the air mix control motor.

NOTICE

Incorrectly applying power and ground to the air mix control motor will damage it.

Follow the instructions carefully.

2. Connect battery power to the No.1 terminal of the air mix control motor, and ground the No.2 terminal; the air mix control motor should run, and stop at Max Hot. If it doesn't, reverse the connections; the air mix control motor should run, and stop at Max Cool. When the air mix control motor stops running, disconnect battery power immediately.

3. If the air mix control motor did not run in step 2, remove it, then check the air mix control linkage and door for smooth movement.

4. Measure the resistance between the No.5 and No.7 terminals. It should be between 4.2 to 7.8 k Ω.

5. Reconnect the air mix control motor 7P connector, then turn the ignition switch ON (II).

6. Using the backprobe set, measure the voltage between the No.3 and No.7 terminals.

Max Cool: about 0.5 V
Max Hot: about 4.5 V

7. If either the resistance or voltage readings are not as specified, replace the air mix control motor.

Air Mix Control Motor Replacement

1. Disconnect the 7P connector (A) from the air mix control motor (B). Remove the self-tapping screws and the air mix control motor from the heater unit.

Honda CR-V. HVAC (Heating, Ventilation, and Air Conditioning)

2. Install the motor in the reverse order of removal.

Make sure the pin on the motor is properly engaged with the linkage. After installation, make sure the motor runs smoothly.

Mode Control Motor Test

NOTE: Before testing, check for HVAC DTCs.

1. Disconnect the 7P connector from the mode control motor.

NOTICE

Incorrectly applying power and ground to the mode control motor will damage it.

Follow the instructions carefully.

2. Connect battery power to the No.1 terminal of the mode control motor, and ground the No.2 terminal; the mode control motor should run smoothly, and stop at Vent. If it doesn't, reverse the connections; the mode control motor should run smoothly, and stop at Defrost. When the mode control motor stops running, disconnect battery power immediately.

Honda CR-V. HVAC (Heating, Ventilation, and Air Conditioning)

3. If the mode control motor did not run in step 2, remove it, then check the mode control linkage and doors for smooth movement.

4. Use a digital multi meter with an output of 1 mA or less at the 20 k Ω range. With the mode control motor running as in step 2, check for continuity between the No.3, 4, 5, and 6 terminals and the No.7 terminal individually. There should be continuity for a moment at each terminal as the motor moves past the switch's terminal.

5. If there is no continuity for a moment at each terminal, replace the mode control motor.

Mode Control Motor Replacement

1. Remove the glove box.

2. Remove the wire harness clips (A), the self-tapping screws, and the passenger's heater duct (B).

Honda CR-V. HVAC (Heating, Ventilation, and Air Conditioning)

3. Disconnect the 7P connector (A) from the mode control motor (B). Remove the self-tapping screws and the mode control motor from the heater unit.

Honda CR-V. HVAC (Heating, Ventilation, and Air Conditioning)

4. Install the motor in the reverse order of removal.

Make sure the pin on the motor is properly engaged with the linkage. After installation, make sure the motor runs smoothly.

Recirculation Control Motor Test

NOTE: Before testing, check for HVAC DTCs.

1. Disconnect the 7P connector from the recirculation control motor.

NOTICE

Incorrectly applying power and ground to the recirculation control motor will damage it.

Follow the instructions carefully.

2. Connect battery power to the No.1 terminal of the recirculation control motor, and ground the No.5 and No.7 terminals; the recirculation control motor should run smoothly. To avoid damaging the recirculation control motor, do not reverse power and ground. Disconnect the No.5 or No.7 terminals from ground; the recirculation control motor should stop at Fresh (when the No.5 terminal is disconnected) or Recirculate (when the No.7 terminal is disconnected). Don't cycle the recirculation control motor for a long time.

Honda CR-V. HVAC (Heating, Ventilation, and Air Conditioning)

3. If the recirculation control motor did not run in step 2, remove it, then check the recirculation control linkage and door for smooth movement.

Recirculation Control Motor Replacement

1. Remove the glove box.

2. Disconnect the 7P connector (A) from the recirculation control motor (B). Remove the self-tapping screws and the recirculation control motor from the blower unit.

Honda CR-V. HVAC (Heating, Ventilation, and Air Conditioning)

3. Install the motor in the reverse order of removal.

Make sure the pin on the motor is properly engaged with the linkage. After installation, make sure the motor runs smoothly.

HVAC Control Unit Removal/Installation

1. Move the shift lever to position 1.

2. Place protective tape (A) on both sides of the dashboard next to the HVAC control unit.

Honda CR-V. HVAC (Heating, Ventilation, and Air Conditioning)

3. Insert a flat-tip screwdriver in the groove on each side, then pull straight out on both screwdriver shafts.

NOTE: Do not pry with the flat-tip screwdrivers.

Honda CR-V. HVAC (Heating, Ventilation, and Air Conditioning)

4. Remove the HVAC control unit (A). Disconnect the connector (B), then remove the harness clip (C).

Honda CR-V. HVAC (Heating, Ventilation, and Air Conditioning)

5. Install the control panel in the reverse order of removal. After installation, operate the various functions to make sure they work properly.

6. Run the self-diagnosis function to confirm that there are no problem in the system.

Dust and Pollen Filter Replacement

1. Open the glove box. Remove the glove box stop on right side, then let the glove box hang down.

2. Remove the dust and pollen filter assembly (A) from the evaporator.

Honda CR-V. HVAC (Heating, Ventilation, and Air Conditioning)

3. Remove the filter (A) from the housing (B), and replace the filter.

Honda CR-V. HVAC (Heating, Ventilation, and Air Conditioning)

4. Install the filter in the reverse order of removal.

Make sure that there is no air leaking out of the blower unit.

READ NEXT:

 Blower Unit Removal/Installation

1. Remove the glove box. 2. Disconnect the connector (A), then remove the connector clip (B), the wire harness clips (C), the bolts, and the glove box frame (D). 3. Cut the plastic cross brace (A) i

 Evaporator Core Replacement

1. Recover the refrigerant with a recovery/recycling/ charging station. 2. Remove the bolt from the A/C line clamp, and remove the receiver line (A) from the clips (B). 3. Remove the nut, then disco

 Heater Unit/Core Replacement

SRS components are located in this area. Review the SRS component locations, and the precautions and procedures before doing repairs or service. 1. Make sure you have anti-theft codes for the audio sy

SEE MORE:

 Moonroof

If equipped The moonroof can be tilted up in the back for ventilation, or it can be slid back into the roof. Use the switch on the front ceiling to operate the moonroof. You must turn the ignition switch to the ON (II) position to operate the moonroof. To tilt up the moonroof, push

 Shift Lever

Shift Lever Removal 1. Remove the following parts: Heater control panel Dashboard center panel Center lower covers 2. Shift the shift lever into the R position. 3. Remove the nut securing the shift cable end. 4. Unlock the retainer (A). 5. Rotate the socket holder retainer (A) counterclockw

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