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Climate Control Unit Inspection (Manual A/C): Notes

WARNING: This page is about a different car, the 2016 Mazda CX-5. However, it is still accessible from the selected car via links, so may be relevant.
  1. Remove the climate control unit with the connector connected. (See CLIMATE CONTROL UNIT REMOVAL/INSTALLATION (MANUAL A/C) .)
  2. Switch the ignition ON (engine off or on).
  3. Connect the negative (-) lead of the tester to the body ground.
  4. By inserting the positive (+) lead of the tester into the climate control unit connector, 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.
      • For terminal Q, first try replacing the blower fan controller. If there is still any malfunction, replace the climate control unit.
    Fig 1: Identifying Climate Control Unit Connector Terminals
    G10937658Courtesy of MAZDA MOTORS CORP.
TERMINAL VOLTAGE SPECIFICATION (REFERENCE)

Terminal 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, good/no good judgment by terminal voltage is not possible.
  • Related wiring harness
C Ground 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, good/no good judgment by terminal voltage is not possible.
  • Related wiring harness
E Sensor GND
  • Evaporator temperature sensor
  • Air mix actuator
  • Airflow mode actuator
Under any condition 1.0 or less
  • Related wiring harness
  • Evaporator temperature sensor
  • Air mix actuator
  • Airflow mode actuator
F - - - - -
G Potentiometer input Air mix actuator Set temperature at MAX HOT 4.3 or more
  • Related wiring harness
  • Air mix actuator
  • Climate control unit: terminal voltage (E)
Set temperature at MAX COLD 1.0 or less
H +5V
  • Air mix actuator
  • Airflow mode actuator
Under any condition 5
  • Related wiring harness
  • Air mix actuator
  • Airflow mode actuator
  • Climate control unit: terminal voltage (E)
I Potentiometer input Airflow mode actuator VENT 4.3 or more
  • Related wiring harness
  • Airflow mode actuator
  • Climate control unit: terminal voltage (E)
BI-LEVEL 3.4
HEAT 2.5
HEAT/DEF 0.72 or less
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+ ROOM 15 A fuse Under any condition B+
  • Related wiring harness
  • ROOM 15 A fuse
M - - - - -
N IG2 Front body control module (FBCM) Switch the ignition to ON (engine off or on) B+
  • Related wiring harness
  • Front body control module (FBCM)
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 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 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 VEVNT 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
Fig 2: Evaporator Temperature Sensor Voltage And Temperature Graph
G10937659Courtesy of MAZDA MOTORS CORP.