NO.4 NO TEMPERATURE CONTROL WITH CLIMATE CONTROL UNIT [FULL-AUTO AIR CONDITIONER]SM2445608
NO.4 NO TEMPERATURE CONTROL WITH CLIMATE CONTROL UNIT [FULL-AUTO AIR CONDITIONER]

id0702c1812400

4
No temperature control with climate control unit
DESCRIPTION
• Temperature does not change when operating temperature dial
• Malfunction in A/C unit and/or climate control unit air intake system
POSSIBLE CAUSE
• A/C unit air intake link, air intake crank, air intake rod, malfunction
• Climate control unit rack-and-pinion, air intake wire malfunction
• A/C unit air mixture door malfunction
• Heater piping malfunction

Diagnostic procedure

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 8.
2*
INSPECT CLIMATE CONTROL UNIT POWER SUPPLY FUSE FOR B+ SIGNAL
• Is the climate control unit power supply fuse for B+ signal normal?.
Yes
Go to the next step.
No
Inspect for short to GND blown fuse circuit.
Repair or replace as necessary.
Install appropriate amperage fuse.
Then go to Step 20.
3*
INSPECT TO SEE WHETHER MALFUNCTION (OPEN CIRCUIT) IS IN B+ SIGNAL WIRING HARNESS (BETWEEN FUSE BLOCK AND CLIMATE CONTROL UNIT) OR ELSEWHERE.
• Disconnect the climate control unit connector (24-pin).
• Switch the ignition to ON.
• Measure voltage at climate control unit harness-side connector (24-pin) terminal 1R (B+ signal).
• Is the voltage approx. 12V?
Yes
Go to the next step.
No
Repair wiring harness between fuse block and climate control unit, then go to Step 20.
*4
INSPECT TO SEE WHETHER MALFUNCTION (LACK OF CONTINUITY) WIRING HARNESS (BETWEEN CLIMATE CONTROL UNIT AND GND) OR ELSEWHERE
• Climate control unit connector (24-pin) disconnected.
• Verify that continuity between climate control unit harness-side connector (24-pin) terminal 1D and GND.
• Is the continuity?
Yes
Go to the next step.
No
Repair wiring harness between climate control unit and GND.
Inspect the GND point.
Then go to Step 20.
*5
INSPECT TO SEE WHETHER MALFUNCTION IS IN BLOWER UNIT OR AIR MIX ACTUATOR
• Switch the ignition to ON.
• Measure the voltage at climate control unit terminal 1X (24-pin) when temperature control dial at MAX HOT and MAX COLD. (See CLIMATE CONTROL UNIT INSPECTION [FULL-AUTO AIR CONDITIONER].)
• Is voltage normal?
Yes
Go to Step 16.
No
Go to the next step.
*6
INSPECT TO SEE WHETHER MALFUNCTION IS IN POTENTIOMETER OR ELSEWHERE
• Switch the ignition to ON.
• Measure voltage at climate control unit terminal 1P (24-pin) when airflow mode change to DEFROSTER and VENT. (See CLIMATE CONTROL UNIT INSPECTION [FULL-AUTO AIR CONDITIONER].)
• Is voltage normal?
Yes
Go to Step 9.
No
Go to the next step.
*7
INSPECT TO SEE WHETHER MALFUNCTION (LACK OF CONTINUITY OR SHORT TO BATTERY POWER OR GND) IS IN POTENTIOMETER POWER SUPPLY (CLIMATE CONTROL UNIT TERMINAL 1J) OR ELSEWHERE
• Switch the ignition to ON.
• Measure voltage at climate control unit terminal 1J (24-pin).
• Is voltage approx. 5V?
Yes
Go to the next step.
No
Repair wiring harness between climate control unit terminal 1J and follows:
• Air mix actuator terminal A
Then go to Step 20.
*8
INSPECT TO SEE WHETHER MALFUNCTION (LACK OF CONTINUITY OR OPEN) IS IN POTENTIOMETER GND (CLIMATE CONTROL UNIT TERMINAL 1C) OR ELSEWHERE
• Measure voltage at climate control unit terminal 1C (24-pin).
• Is the voltage below. 1.0V?
Yes
Go to Step 12.
No
Repair wiring harness between climate control unit terminal 1C and follows:
• Air mix actuator terminal B
Then go to Step 20.
9
INSPECT TO SEE WHETHER MALFUNCTION (SHORT TO POWER) IS IN WIRING HARNESS (AIR MIX POSITION SIGNAL) OR ELSEWHERE
• Is climate unit terminal 1X voltage approx. 12 V, at Step 5?
Yes
Repair wiring harness for short to power between climate control unit terminal 1X and air mix actuator terminal C.
Then go to Step 20.
No
Go to the next step.
*10
INSPECT TO SEE WHETHER MALFUNCTION (LACK OF CONTINUITY) IS IN WIRING HARNESS (AIR MIX POSITION SIGNAL) OR ELSEWHERE
• Switch the ignition to off.
• Disconnect the climate control and air mix actuator connectors.
• Verify continuity between climate control unit terminal 1X (24-pin) and air mix actuator terminal C at harness-side connector.
• Is there continuity?
Yes
Go to the next step.
No
Repair wiring harness between climate control unit terminal 1X and air mix actuator terminal C.
Then go to Step 20.
*11
INSPECT TO SEE WHETHER MALFUNCTION (SHORT TO GND) IS IN WIRING HARNESS (AIR MIX POSITION SIGNAL) OR POTENTIOMETER COMMON (POWER SUPPLY OR GND) HARNESS
• Verify continuity between climate control unit harness-side connector terminal 1X (24-pin) and GND.
• Is there continuity?
Yes
Repair wiring harness for short to GND between climate control unit terminal 1X and air mix actuator terminal C.
Then go to Step 20.
No
Inspect and repair for open circuit following:
• Between air mix actuator terminal A and junction point to airflow mode actuator (potentiometer power supply).
• Between air mix actuator terminal B and junction point to airflow mode actuator (potentiometer power GND).
Then go to Step 20.
*12
INSPECT TO SEE WHETHER MALFUNCTION (LACK OF CONTINUITY) IS IN AIR MIX ACTUATOR WIRING HARNESS (BETWEEN CLIMATE CONTROL UNIT AND AIR MIX ACTUATOR)
• Disconnect the air mix actuator connector.
• Measure voltage at the following terminals of air mix actuator.
― Terminal D (COLD motor drive signal)
― Terminal F (HOT motor drive signal)
• Are voltages as shown below?
― COLD motor drive signal: approx. 10V during COLD and approx. 0.5V during HOT
― HOT motor drive signal: approx. 0.5V during COLD and approx. 0.5V during HOT
Yes
Go to Step 16.
No
Go to the next step.
*13
INSPECT TO SEE WHETHER MALFUNCTION IS IN WIRING HARNESS (SHORT TO B+ BETWEEN CLIMATE CONTROL UNIT AND AIR MIX ACTUATOR) OR ELSEWHERE
• Air mix actuator connector disconnected.
• Disconnect the climate control unit connector.
• Measure voltage at the following terminals of air mix actuator harness-side connector.
― Terminal D (COLD motor drive signal)
― Terminal F (HOT motor drive signal)
• Are the voltage approx. 0V?
Yes
Go to the next step.
No
Repair wiring harness between climate control unit and air mix actuator.
Then go to Step 20.
*14
INSPECT TO SEE WHETHER MALFUNCTION IS IN AIR MIX ACTUATOR OR ELSEWHERE
• Air mix actuator connector and climate control unit connector disconnected.
• Switch the ignition to off.
• Verify that continuity at the following harness-side connector terminals between air mix actuator and GND.
― Terminal D (COLD motor drive signal)
― Terminal F (HOT motor drive signal)
• Is there continuity?
Yes
Repair wiring harness for short to GND between climate control unit and air mix actuator.
Then go to Step 20.
No
Go to the next step.
*15
INSPECT TO SEE WHETHER MALFUNCTION IS IN WIRING HARNESS (OPEN CIRCUIT BETWEEN CLIMATE CONTROL UNIT AND AIR MIX ACTUATOR) OR ELSEWHERE
• Air mix actuator connector and climate control unit connector disconnected.
• Switch the ignition to off.
• Verify that continuity at the following harness-side connector terminals between air mix actuator and GND.
― Climate control unit terminal 1U— air mix actuator terminal D (COLD motor drive signal)
― Climate control unit terminal 1S— air mix actuator terminal F (HOT motor drive signal)
• Is there continuity?
Yes
Go to the next step.
No
Repair wiring harness for open circuit between climate control unit and air mix actuator.
Then go to Step 20.
16
INSPECT AIR MIX ACTUATOR
• Inspect the air mix actuator. (See AIR MIX ACTUATOR INSPECTION [FULL-AUTO AIR CONDITIONER].)
• Is air mix actuator normal?
Yes
Go to the next step.
No
Replace the air mix actuator.
Then go to 20.
(See AIR MIX ACTUATOR REMOVAL/INSTALLATION [FULL-AUTO AIR CONDITIONER].)
17
INSPECT AIR MIX LINK
• Inspect air mix links for following.
― Is grease on links?
― Are links securely and properly installed?
― Are links free of obstructions and hindrances?
• Are above items okay?
Yes
Go to the next step.
No
Apply grease to links.
If any links are damaged. replace malfunctioning part.
Then go to Step 20.
18
INSPECT TO SEE WHETHER MALFUNCTION IS IN CLIMATE CONTROL UNIT OR AIR MIX DOOR ELSEWHERE
• Inspect A/C unit and each-side air mix door.
― Is door free of unit and obstruction, and damage?
― Are doors securely and properly installed?
• Are above items okay?
Yes
Go to the next step.
No
Remove the obstruction, or install door in proper position.
If any door are cracked, replace them.
Then go to Step 20.
19
INSPECT HEATER LINE
• Inspect the heater lines.
― Is the heater piping free of damage and cracks?
― Are the heater piping connections free of engine coolant leakage?
― Are the heater piping connections securely tightened?
― Are the heater piping installation points on A/C unit free of engine coolant leakage?
• Are the above items normal?
Yes
Operation is normal. Recheck malfunction symptoms.
No
If heater piping connections are loose, tighten the connections to the specified torque.
Repair or replace the heater piping, then go to the next step.
20
VERIFY THAT MALFUNCTION SYMPTOM OCCURS AFTER REPAIR
• Does the unit operate in every temperature setting?
Yes
Troubleshooting completed.
Explain repairs to customer.
No
Recheck malfunction symptoms, then repeat from Step 1 if the malfunction recurs.