Climate Control Unit Inspection: Notes
WARNING: This page is about a different car, the 2016 Mazda MX-5 Miata. However, it is still accessible from the selected car via links, so may be relevant.
- Disconnect the negative battery cable. (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION .)
- Remove the following parts:
- Selector lever knob (AT) (See AUTOMATIC TRANSMISSION SHIFT MECHANISM REMOVAL/INSTALLATION .)
- Shift lever knob (MT)
- Shift panel component (See SHIFT PANEL REMOVAL/INSTALLATION .)
- Upper panel (See UPPER PANEL REMOVAL/INSTALLATION .)
- Parking brake lever boot panel (See PARKING BRAKE LEVER BOOT PANEL REMOVAL/INSTALLATION .)
- Rear console (See REAR CONSOLE REMOVAL/INSTALLATION .)
- Front console panel (See FRONT CONSOLE PANEL REMOVAL/INSTALLATION .)
- Front console component (See FRONT CONSOLE REMOVAL/INSTALLATION .)
- Scuff plate (See SCUFF PLATE REMOVAL/INSTALLATION .)
- Front side trim (See FRONT SIDE TRIM REMOVAL/INSTALLATION .)
- A-pillar trim (See A-PILLAR TRIM REMOVAL/INSTALLATION .)
- Hood release lever (See HOOD RELEASE LEVER AND RELEASE CABLE REMOVAL/INSTALLATION .)
- Driver-side lower panel (See DRIVER-SIDE LOWER PANEL REMOVAL/INSTALLATION .)
- Passenger-side lower panel (See PASSENGER-SIDE LOWER PANEL REMOVAL/INSTALLATION .)
- Center panel No. 1 (See CENTER PANEL No. 1 REMOVAL/INSTALLATION .)
- Remove the climate control unit with the connector connected. (See CLIMATE CONTROL UNIT REMOVAL/INSTALLATION .)
- Connect the negative battery cable. (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION .)
- Switch the ignition ON (engine off or on).
- Connect the negative (-) lead of the tester to the body ground.
- Insert the positive (+) lead of the tester into each climate control unit terminal and measure the voltage according to the terminal voltage table.
- If there is any malfunction, inspect the parts under "Inspection item (s)".
- If the parts under "Inspection item (s)" are found to be normal (except for terminal Q), replace the climate control unit. (See CLIMATE CONTROL UNIT REMOVAL/INSTALLATION .)
- For terminal Q, first try replacing the blower fan controller. If there is still any malfunction, replace the climate control unit. (See CLIMATE CONTROL UNIT REMOVAL/INSTALLATION .)
TERMINAL VOLTAGE REFERENCETerminal Signal name Connected to Measurement condition Voltage (V) Inspection item (s) A - - - - - B MS_CAN_L CAN related module Because this terminal is for communication, integrity determination by terminal voltage is not possible. - Related wiring harness
C GND Body ground Under any condition 1.0 or less - Related wiring harness
D MS_CAN_H CAN related module Because this terminal is for communication, integrity determination by terminal voltage is not possible. - Related wiring harness
E Sensor GND - Air mix actuator
- Airflow mode actuator
- Evaporator temperature sensor
Under any condition 1.0 or less - Related wiring harness
- Climate control unit: terminal voltage (H)
F - - - - - G Potentiometer input Air mix actuator Set temperature at HOT 0.5 or more - Related wiring harness
- Climate control unit: terminal voltage (E)
Set temperature at COLD 4.47 or less H +5V - Air mix actuator
- Airflow mode actuator
Under any condition 5 - Related wiring harness
- Climate control unit: terminal voltage (E)
I Potentiometer input Airflow mode actuator VENT 0.5 or less - Related wiring harness
- Airflow mode actuator
- Climate control unit: terminal voltage (E)
BI-LEVEL 1.47 HEAT 2.47 HEAT/DEF 3.48 DEFROSTER 4.47 or more J Evaporator temperature sensor input Evaporator temperature sensor Compared with temperature detected by evaporator temperature sensor Refer to graph 1 - Related wiring harness
- Evaporator temperature sensor
- Climate control unit: terminal voltage (E)
K - - - - - L B+ - INTERIOR 15 A fuse
- ROOM 25 A fuse
Under any condition B+ - Related wiring harness
- INTERIOR 15 A fuse
- ROOM 25 A fuse
M - - - - - N IG1 Ignition relay Switch the ignition ON (engine off or on) B+ - Related wiring harness
- Ignition relay
Switch the ignition off 1.0 or less O - - - - - P - - - - - Q Blower fan speed control Blower fan controller (See BLOWER FAN SPEED CONTROL SIGNAL .) - Related wiring harness
- Blower fan controller
R - - - - - S Motor operation (RECIRCULATE) Air intake actuator Moving towards RECIRCULATE B+ - Related wiring harness
- Air intake actuator
Moving towards FRESH 1.0 or less T Motor operation (VENT) Airflow mode actuator Moving towards VENT B+ - Related wiring harness
- Airflow mode actuator
Moving towards DEFROSTER 1.0 or less U Motor operation (FRESH) Air intake actuator Moving towards RECIRCULATE 1.0 or less - Related wiring harness
- Air intake actuator
Moving towards FRESH B+ V Motor operation (DEFROSTER) Airflow mode actuator Moving towards DEFROSTER B+ - Related wiring harness
- Airflow mode actuator
Moving towards VENT 1.0 or less W Motor operation (COLD) Air mix actuator Moving towards HOT 1.0 or less - Related wiring harness
- Air mix actuator
Moving towards COLD B+ X Motor operation (HOT) Air mix actuator Moving towards HOT B+ - Related wiring harness
- Air mix actuator
Moving towards COLD 1.0 or less - If there is any malfunction, inspect the parts under "Inspection item (s)".