NO.3 NO TEMPERATURE CONTROL WITH CLIMATE CONTROL UNIT

id070300802400

3
No temperature control with climate control unit.
DESCRIPTION
•  Temperature does not change with operating temperature control dial.
POSSIBLE CAUSE
•  Air mix actuator (+5 V signal) system malfunction
•  climate control unit (potentiometer GND signal) system malfunction
•  Air mix actuator (potentiometer input signal) system malfunction
•  Air mix actuator (potentiometer GND signal, motor drive signal) system malfunction
•  Air mix actuator system malfunction
•  Heater unit air mix door malfunction

•  When performing an asterisked (*) troubleshooting inspection, shake the wiring harness and connectors while performing the inspection to discover whether poor contact points are the cause of any intermittent malfunctions. If there is a problem, check to make sure connectors, terminals and wiring harnesses are connected correctly and undamaged.

Diagnostic procedure

STEP

INSPECTION

ACTION
1
INSPECT COOLANT TEMPERATURE
•  Is coolant sufficiently warmed up?
Yes
Go to next step.
No
Warm engine up, then go to Step 19.
2
CHECK CIRCUITS COMMON TO BOTH AIR MIX ACTUATOR AND AIRFLOW MODE ACTUATOR
•  Does airflow mode change when operating airflow mode selector switch?
Yes
Go to Step 10.
No
Go to next step.
3
CHECK TO SEE WHETHER PROBLEM IS IN AIR MIX ACTUATOR +5 V SIGNAL OR POTENTIOMETER GND SIGNAL
•  Is air mix actuator set at MAX HOT and airflow mode actuator at VENT?
(Verify position of air mix actuator link and airflow mode actuator link.)
Yes
Go to next step.
No
Go to Step 8. (Set actuator at MAX COLD and DEFROSTER.)
4*
CHECK TO SEE WHETHER MALFUNCTION (LACK OF CONTINUITY) IS IN WIRING HARNESS (BETWEEN CLIMATE CONTROL UNIT AND AIR MIX ACTUATOR) OR ELSEWHERE
•  Turn the ignition switch to ON position.
•  Is there voltage of approx. 5 V at climate control unit connector terminal U (+5 V signal)?
Yes
Repair wiring harness between climate control unit and air mix actuator, then go to Step 19.
No
Go to next step.
5*
CHECK TO SEE WHETHER MALFUNCTION IS IN AIR MIX ACTUATOR (SHORT TO GROUND) OR ELSEWHERE
•  Disconnect air mix actuator connector.
•  Is there voltage of approx. 5 V at climate control unit connector terminal U (+5 V signal)?
Yes
Inspect air mix actuator, then go to Step 19.
No
Go to next step.
6*
CHECK TO SEE WHETHER MALFUNCTION IS IN AIRFLOW MODE ACTUATOR (SHORT TO GROUND) OR ELSEWHERE
•  Disconnect airflow actuator connector.
•  Is there voltage of approx. 5 V at climate control unit connector terminal U (+5 V signal)?
Yes
Inspect airflow mode actuator, then go to Step 19.
No
Go to next step.
7*
CHECK TO SEE WHETHER MALFUNCTION (SHORT TO GROUND) IS IN CLIMATE CONTROL UNIT OR WIRING HARNESS (BETWEEN CLIMATE CONTROL UNIT AND AIR MIX ACTUATOR)
•  Disconnect climate control unit connector.
•  Is there continuity between climate control unit connector terminal U (+5 V signal) and ground?
Yes
Repair wiring harness between climate control unit and air mix actuator, then go to Step 19.
No
Replace climate control unit, then go to Step 19.
8*
CHECK TO SEE WHETHER MALFUNCTION (LACK OF CONTINUITY) IS IN CLIMATE CONTROL UNIT OR WIRING HARNESS (BETWEEN CLIMATE CONTROL UNIT AND AIR MIX ACTUATOR)
•  Disconnect climate control unit connector and air mix actuator connector.
•  Is there continuity between climate control unit connector terminal V (potentiometer GND signal) and air mix actuator connector terminal E?
Yes
Go to next step.
No
Repair wiring harness between climate control unit and air mix actuator, then go to Step 19.
9*
CHECK TO SEE WHETHER MALFUNCTION (SHORT TO B+) IS IN CLIMATE CONTROL UNIT OR WIRING HARNESS (BETWEEN CLIMATE CONTROL UNIT AND AIR MIX ACTUATOR)
•  Turn the ignition switch to ON position.
•  Test voltage at climate control unit connector and terminal V (potentiometer GND signal).
•  Is voltage approx. 12 V?
Yes
Repair wiring harness between climate control unit and air mix actuator, then go to Step 19.
No
Replace climate control unit, then go to Step 19.
10*
CHECK TO SEE WHETHER MALFUNCTION (LACK OF CONTINUITY) IS IN WIRING HARNESS (BETWEEN CLIMATE CONTROL UNIT AND AIR MIX ACTUATOR) OR ELSEWHERE
•  Turn the ignition switch to ON position.
•  Test voltage at air mix actuator connector terminal E (+5 V signal).
•  Is voltage approx. 5 V?
Yes
Go to next step.
No
Repair wiring harness between climate control unit and air mix actuator, then go to Step 19.
11*
CHECK TO SEE WHETHER MALFUNCTION (LACK OF CONTINUITY) IS IN WIRING HARNESS (BETWEEN CLIMATE CONTROL UNIT AND AIR MIX ACTUATOR) OR ELSEWHERE
•  Turn the ignition switch to LOCK position.
•  Disconnect climate control unit connector and air mix actuator connector.
•  Is there continuity between climate control unit connector terminal X (potentiometer input signal) and air mix actuator connector terminal B?
Yes
Go to next step.
No
Repair wiring harness between climate control unit and air mix actuator, then go to Step 19.
12*
CHECK TO SEE WHETHER MALFUNCTION (SHORT TO GROUND) IS IN WIRING HARNESS (BETWEEN CLIMATE CONTROL UNIT AND AIR MIX ACTUATOR) OR ELSEWHERE
•  Is there continuity between climate control unit connector terminal X (potentiometer input signal) and ground?
Yes
Repair wiring harness between climate control unit and air mix actuator, then go to Step 19.
No
Go to next step.
13*
CHECK TO SEE WHETHER MALFUNCTION (SHORT TO B+) IS IN WIRING HARNESS (BETWEEN CLIMATE CONTROL UNIT AND AIR MIX ACTUATOR) OR ELSEWHERE
•  Turn the ignition switch to ON position.
•  Test voltage at climate control unit connector terminal X (potentiometer input signal).
•  Is voltage approx. 12 V?
Yes
Repair wiring harness between climate control unit and air mix actuator, then go to Step 19.
No
Go to next step.
14*
CHECK TO SEE WHETHER MALFUNCTION (LACK OF CONTINUITY) IS IN WIRING HARNESS (BETWEEN CLIMATE CONTROL UNIT AND AIR MIX ACTUATOR) OR ELSEWHERE
•  Turn the ignition switch to LOCK position.
•  Is there continuity between following climate control unit connector terminals and air mix actuator connector terminals?
―  Terminal V and terminal E (potentiometer GND signal)
―  Terminal L and terminal F (motor drive signal)
―  Terminal K and terminal A (motor drive signal)
Yes
Go to next step.
No
Repair wiring harness between climate control unit and air mix actuator, then go to Step 19.
15
INSPECT HEATER UNIT AIR MIX ACTUATOR LINK AND CRANK
•  Is there grease on the link and crank?
Yes
Go to next step.
No
Apply grease, then go to Step 19.
16
INSPECT AIR MIX ACTUATOR
•  Inspect air mix actuator.
•  Is it normal?
Yes
Go to next step.
No
Replace air mix actuator, then go to Step 19.
17
VERIFY THAT HEATER UNIT AIR MIX DOORS DO NOT HAVE ANY FOREIGN MATERIAL OR OBSTRUCTION
•  Is there any foreign material or obstructions on any heater unit door?
Yes
Remove material/obstruction, then go to Step 19.
No
Go to next step.
18
INSPECT HEATER UNIT AIR MIX DOORS
•  Are all doors within heater unit securely and properly positioned?
•  Inspect heater unit doors.
―  Are doors cranked or damaged?
―  Are doors securely and properly installed?
•  Are they normal?
Yes
Replace climate control unit, then go to next step.
(Malfunction in climate control unit temperature control lever circuit)
No
Replace or install door(s) in proper position, then go to next step.
19
CONFIRM THAT MALFUNCTION SYMPTOMS DO NOT RECUR AFTER REPAIR
•  Does temperature change when operating temperature control dial?
Yes
Troubleshooting completed.
Explain repairs to customer.
No
Recheck malfunction symptoms, then repeat from Step 1 if malfunction recurs.