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Home >> Mazda >> 2017 >> CX-5 Grand Select, FWD >> Repair and Diagnosis >> Heating, Ventilation & A/C (HVAC) >> HVAC Control Systems >> Symptom Troubleshooting - Manual A/C >> No Temperature Control With Climate Control Unit [Manual Air Conditioner] >> Diagnostic Procedure

Diagnostic Procedure

DIAGNOSTIC PROCEDURE DESCRIPTION

Step Inspection Action
1 INSPECT COOLANT TEMPERATURE
  • Is the coolant sufficiently warmed up?
 Yes Go to the next step.
No Warm up the engine, then go to Step 24.
2* INSPECT FUSE Yes Go to the next step.
No If the fuse is blown:
  • Refer to the wiring diagram and verify whether or not there is a common connector between ROOM 15 A fuse and climate control unit terminal.

    If there is a common connector:

    • Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness for a short to ground.
      • Repair or replace the malfunctioning part.

        If there is no common connector:

      • Repair or replace the wiring harness which has a short to ground.
  • Replace the fuse.

    If the fuse is damaged:

  • Replace the fuse.

Then go to Step 24.
3* INSPECT TO SEE WHETHER MALFUNCTION (OPEN CIRCUIT) IS IN B+ SIGNAL WIRING HARNESS (BETWEEN FUSE BLOCK AND CLIMATE CONTROL UNIT) OR ELSEWHERE Yes Go to the next step.
No Refer to the wiring diagram and verify whether or not there is a common connector between fuse block terminal and climate control unit terminal.
If there is a common connector:
  • Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness for an open circuit.
  • Repair or replace the malfunctioning part.

    If there is no common connector:

  • Repair or replace the wiring harness which has an open circuit.

Go to Step 24.
4* INSPECT TO SEE WHETHER MALFUNCTION IS IN A/C UNIT OR AIR MIX ACTUATOR Yes Go to Step 22.
No Go to the next step.
5* INSPECT TO SEE WHETHER MALFUNCTION IS IN POSITION SENSOR OR ELSEWHERE
  • Measure voltage at the following terminal (wiring harness-side) when airflow mode at VENT and DEFROSTER.
    • Climate control unit terminal K
  • Is voltage normal?
 Yes Go to Step 8.
No Go to the next step.
6* INSPECT TO SEE WHETHER MALFUNCTION (SHORT TO BATTERY POWER OR GROUND) IS IN POSITION SENSOR POWER SUPPLY OR ELSEWHERE
  • Measure voltage at the following terminal (wiring harness-side).
    • Climate control unit terminal L
  • Is voltage approx. 5 V?
 Yes Go to the next step.
No Refer to the wiring diagram and verify whether or not there is a common connector between climate control unit terminal and each actuator/sensor terminal.
If there is a common connector:
  • Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness.
  • Repair or replace the malfunctioning part.

    If there is no common connector:

  • Repair or replace the wiring harness.

Go to Step 24.
7* INSPECT TO SEE WHETHER MALFUNCTION (SHORT TO POWER SUPPLY) IS IN POSITION SENSOR GROUND OR ELSEWHERE
  • Measure voltage at the following terminal (wiring harness-side).
    • Climate control unit terminal R
  • Is the voltage below 1.0 V?
 Yes Refer to wiring diagram and inspect for open circuit following.
  • Between climate control unit terminal L and junction point to actuators/sensors (position sensor power supply).
  • Between climate control unit terminal R and junction point to actuators/sensors (position sensor ground). Repair or replace the malfunctioning part or wiring harness.

Go to Step 24.
No Refer to the wiring diagram and verify whether or not there is a common connector between climate control unit terminal and each actuator/sensor terminal.
If there is a common connector:
  • Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness.
  • Repair or replace the malfunctioning part.

    If there is no common connector:

  • Repair or replace the wiring harness.

Go to Step 24.
8 INSPECT TO SEE WHETHER MALFUNCTION (SHORT TO POWER SUPPLY) IS IN WIRING HARNESS (AIR MIX POSITION SIGNAL) OR ELSEWHERE
  • Is the voltage B+, at Step 4?
 Yes Refer to the wiring diagram and verify whether or not there is a common connector between climate control unit terminal and air mix actuator terminal.
If there is a common connector:
  • Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness for a short to power supply.
  • Repair or replace the malfunctioning part.

    If there is no common connector:

  • Repair or replace the wiring harness which has a short to power supply.

Go to Step 24.
No Go to the next step.
9 INSPECT CLIMATE CONTROL UNIT CONNECTOR CONNECTION CONDITION Yes Go to the next step.
No Reconnect the climate control unit connector properly.
Go to Step 24.
10 INSPECT CLIMATE CONTROL UNIT CONNECTOR TERMINAL CONDITION Yes Go to the next step.
No Repair/replace the connector or terminal.
Go to Step 24.
11 INSPECT AIR MIX ACTUATOR CONNECTOR CONNECTION CONDITION Yes Go to the next step.
No Reconnect the air mix actuator connector properly.
Go to Step 24.
12 INSPECT AIR MIX ACTUATOR CONNECTOR TERMINAL CONDITION Yes Go to the next step.
No Repair/replace the connector or terminal.
Go to Step 24.
13* INSPECT TO SEE WHETHER MALFUNCTION (LACK OF CONTINUITY) IS IN WIRING HARNESS (AIR MIX POSITION SIGNAL) OR ELSEWHERE
  • Inspect continuity between the following terminals (wiring harness-side):
    • Climate control unit terminal I- air mix actuator terminal F
  • Is there continuity?
 Yes Go to the next step.
No Refer to the wiring diagram and verify whether or not there is a common connector between climate control unit terminal and air mix actuator terminal.
If there is a common connector:
  • Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness.
  • Repair or replace the malfunctioning part.

    If there is no common connector:

  • Repair or replace the wiring harness.

Go to Step 24.
14* INSPECT TO SEE WHETHER MALFUNCTION (SHORT TO GROUND) IS IN WIRING HARNESS (AIR MIX POSITION SIGNAL) OR ELSEWHERE
  • Inspect for continuity between the following terminals (wiring harness-side) and body ground:
    • Climate control unit terminal I
  • Is there continuity?
 Yes Refer to the wiring diagram and verify whether or not there is a common connector between climate control unit terminal and air mix actuator terminal.
If there is a common connector:
  • Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness.
  • Repair or replace the malfunctioning part.

    If there is no common connector:

  • Repair or replace the wiring harness.

Go to Step 24.
No Go to the next step.
15* INSPECT TO SEE WHETHER MALFUNCTION (OPEN CIRCUIT) IS IN POSITION SENSOR POWER SUPPLY OR ELSEWHERE
  • Inspect for continuity between the following terminals (wiring harness-side) and junction point to other actuators/sensors (position sensor power supply).
    • Air mix actuator terminal E
  • Is there continuity?
 Yes Go to the next step.
No Refer to the wiring diagram and verify whether or not there is a common connector between air mix actuator terminal and junction point to other actuators/sensor terminal.
If there is a common connector:
  • Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness for an open circuit.
  • Repair or replace the malfunctioning part.

    If there is no common connector:

  • Repair or replace the wiring harness which has an open circuit.

Go to Step 24.
16* INSPECT TO SEE WHETHER MALFUNCTION (OPEN CIRCUIT) IS IN POSITION SENSOR GROUND OR ELSEWHERE
  • Inspect for continuity between the following terminals (wiring harness-side) and junction point to other actuators/sensors (position sensor ground).
    • Air mix actuator terminal G
  • Is there continuity?
 Yes Go to the next step.
No Refer to the wiring diagram and verify whether or not there is a common connector between air mix actuator terminal and junction point to other actuators/sensor terminal.
If there is a common connector:
  • Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness for an open circuit.
  • Repair or replace the malfunctioning part.

    If there is no common connector:

  • Repair or replace the wiring harness which has an open circuit.

Go to Step 24.
17* INSPECT TO SEE WHETHER MALFUNCTION IS IN AIR MIX ACTUATOR OR WIRING HARNESS (LACK OF CONTINUITY BETWEEN CLIMATE CONTROL UNIT AND AIR MIX ACTUATOR) Yes Go to Step 21.
No Go to the next step.
18* INSPECT TO SEE WHETHER MALFUNCTION IS IN WIRING HARNESS (LACK OF CONTINUITY OR OPEN BETWEEN CLIMATE CONTROL UNIT AND AIR MIX ACTUATOR) OR ELSEWHERE Yes Go to the next step.
No Refer to the wiring diagram and verify whether or not there is a common connector between climate control unit terminal and air mix actuator terminal.
If there is a common connector:
  • Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness.
  • Repair or replace the malfunctioning part.

    If there is no common connector:

  • Repair or replace the wiring harness.

Go to Step 24.
19* INSPECT TO SEE WHETHER MALFUNCTION IS IN WIRING HARNESS (SHORT TO B+ BETWEEN CLIMATE CONTROL UNIT AND AIR MIX ACTUATOR) OR ELSEWHERE
  • Climate control unit and air mix actuator connectors are disconnected.
  • Connect the negative battery terminal.

    (See CLIMATE CONTROL UNIT REMOVAL/INSTALLATION [MANUAL AIR CONDITIONER] .)

  • Switch the ignition ON (engine off or on).
  • Measure voltage at the following terminals (wiring harness-side).
    • Climate control unit terminal C (COLD motor drive signal)
      • Climate control unit terminal A (HOT motor drive signal)
  • Are voltages approx. 0 V?
 Yes Go to the next step.
No Refer to the wiring diagram and verify whether or not there is a common connector between climate control unit terminal and air mix actuator terminal.
If there is a common connector:
  • Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness for a short to power supply.
  • Repair or replace the malfunctioning part.

    If there is no common connector:

  • Repair or replace the wiring harness which has a short to power supply.

Go to Step 24.
20* INSPECT TO SEE WHETHER MALFUNCTION IS IN WIRING HARNESS (SHORT TO GROUND BETWEEN CLIMATE CONTROL UNIT AND AIR MIX ACTUATOR) OR ELSEWHERE
  • Switch the ignition off.
  • Climate control unit and air mix actuator connectors disconnected.
  • Inspect for continuity between the following terminals (wiring harness-side) and body ground.
    • Climate control unit terminal C (COLD motor drive signal)
      • Climate control unit terminal A (HOT motor drive signal)
  • Is there continuity?
 Yes Refer to the wiring diagram and verify whether or not there is a common connector between climate control unit terminal and air mix actuator terminal.
If there is a common connector:
  • Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness for a short to ground.
  • Repair or replace the malfunctioning part.

    If there is no common connector:

  • Repair or replace the wiring harness which has a short to ground.

Go to Step 24.
No Go to the next step.
21 INSPECT AIR MIX ACTUATOR Yes Replace the climate control unit.
(See CLIMATE CONTROL UNIT REMOVAL/INSTALLATION [MANUAL AIR CONDITIONER] .)
Go to Step 24.
No Replace the air mix actuator.
(See AIR MIX ACTUATOR REMOVAL/INSTALLATION [MANUAL AIR CONDITIONER] .)
Then go to Step 24.
22 INSPECT AIR MIX LINK Yes Go to the next step.
No Apply grease to links.
If any links are damaged. Replace malfunctioning part.
(See AIR MIX ACTUATOR REMOVAL/INSTALLATION [MANUAL AIR CONDITIONER] .)
Then go to Step 24.
23 INSPECT A/C UNIT AND AIR MIX DOOR
  • Inspect the A/C unit and each-side air mix door. (See A/C UNIT DISASSEMBLY/ASSEMBLY .)
    • Is door free of obstructions and damage?
      • Are doors securely and properly installed?
  • Are the above items normal?
 Yes Inspect the heater hoses.
  • If the heater hoses are not free of damage and cracks, repair or replace the heater hoses.
  • If the heater hose connections are loose, install securely in correct position.

Go to the next step.
No Remove the obstruction, or install door in proper position.
If any doors are cracked, replace them.
(See A/C UNIT DISASSEMBLY/ASSEMBLY .)
Then go to the next step.
24 VERIFY THAT MALFUNCTION SYMPTOM DOES NOT RECUR AFTER REPAIR
  • Does the unit operate at every temperature setting?
 Yes Troubleshooting completed.
Explain repairs to customer.
No Recheck malfunction symptoms, then repeat from Step1 if the malfunction recurs.
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