Rear Climate Control Unit Inspection
WARNING: This page is about a different car, the 2018 Mazda CX-9. However, it is still accessible from the selected car via links, so may be relevant.
- Disconnect the negative battery terminal. (See NEGATIVE BATTERY TERMINAL DISCONNECTION/CONNECTION .)
- Remove the rear console panel. (See REAR CONSOLE REMOVAL/INSTALLATION .)
- Remove the rear climate control unit with the connector connected. (See REAR CLIMATE CONTROL UNIT REMOVAL/INSTALLATION .)
- Connect the negative battery terminal. (See NEGATIVE BATTERY TERMINAL DISCONNECTION/CONNECTION .)
- Switch the ignition ON (engine off or on).
- Connect the negative (-) lead of the tester to body ground.
- Insert the positive (+) lead of the tester into each rear 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 F), replace the rear climate control unit. (See REAR CLIMATE CONTROL UNIT REMOVAL/INSTALLATION .)
- For terminal F, first try replacing the power MOS FET. If there is still any malfunction, replace the rear climate control unit. (See REAR CLIMATE CONTROL UNIT REMOVAL/INSTALLATION .)
- If there is any malfunction, inspect the parts under "Inspection item (s)".
TERMINAL VOLTAGE SPECIFICATION (REFERENCE)
| Terminal | Signal Name | Connected To | Measurement Condition | Voltage (V) | Inspection Item (s) | |||
|---|---|---|---|---|---|---|---|---|
| A | Motor operation (VENT) | Rear airflow mode actuator | Moving towards VENT | B+ | Rear airflow mode actuator | |||
| Moving towards HEAT | 1.0 or less | |||||||
| B | IG2 | Front body control module (FBCM) | Switch the ignition ON (engine off or on) | B+ | Front body control module (FBCM) | |||
| Switch the ignition off | 1.0 or less | |||||||
| C | Motor operation (HEAT) | Rear airflow mode actuator | Moving towards HEAT | B+ | Rear airflow mode actuator | |||
| Moving towards VENT | 1.0 or less | |||||||
| D | - | - | - | - | - | |||
| E | Motor operation (COLD) | Rear air mix actuator | Moving towards HOT | 1.0 or less | Rear air mix actuator | |||
| Moving towards COLD | B+ | |||||||
| F | Blower motor feedback |
|
Fan stopped | B+ |
|
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| Fan: manual 1st | 10.7 | |||||||
| Fan: manual 3rd | 8.4 | |||||||
| Fan: manual 5th | 4.4 | |||||||
| G | Motor operation (HOT) | Rear air mix actuator | Moving towards HOT | B+ | Rear air mix actuator | |||
| Moving towards COLD | 1.0 or less | |||||||
| H | Blower fan speed control |
|
Switch the ignition off | 1.0 or less |
|
|||
| Fan stopped (Switch the ignition ON (engine off or on)) | ||||||||
| Airflow mode: VENT | Fan: manual 1st | 2.2 | ||||||
| Fan: manual 3rd | 2.3 | |||||||
| Fan: manual 5th | 2.5 | |||||||
| I | - | - | - | - | - | |||
| J | - | - | - | - | - | |||
| K | - | - | - | - | - | |||
| L | - | - | - | - | - | |||
| M | - | - | - | - | - | |||
| N | - | - | - | - | - | |||
| O | Sensor GND |
|
Under any condition | 1.0 or less |
|
|||
| P | LIN | Front climate control unit | Because this terminal is for communication, integrity determination by terminal voltage is not possible. | |||||
| Q | Potentiometer input | Rear airflow mode actuator | VENT | 1.0 | Rear airflow mode actuator | |||
| BI-LEVEL | 2.2 | |||||||
| HEAT | 3.5 | |||||||
| R | GND | Body ground | Under any condition | 1.0 or less |
|
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| S | Potentiometer input | Rear air mix actuator | Set temperature at MAX HOT | 3.4 | Rear air mix actuator | |||
| Set temperature at MAX COLD | 1.2 | |||||||
| T(1) | LIN | Rear seat warmer control unit | Because this terminal is for communication, integrity determination by terminal voltage is not possible. | |||||
| U | - | - | - | - | - | |||
| V | B+ |
|
Under any condition | B+ |
|
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| W | +5V |
|
Under any condition | 5 |
|
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| X | IG1 | C/U IG1 15 A fuse | Switch the ignition ON (engine off or on) | B+ | C/U IG1 15 A fuse | |||
| Switch the ignition off | 1.0 or less | |||||||
|
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