NO TEMPERATURE CONTROL WITH REAR CLIMATE CONTROL UNIT [CLIMATE CONTROL SYSTEM]

id0703k2901100

DESCRIPTION
•  Temperature does not change when operating temperature control switch
•  Malfunction in A/C unit and/or rear climate control unit air mix system
•  Malfunction in rear air mix actuator or related wiring harness
POSSIBLE CAUSE
•  ROOM 25 A fuse malfunction
•  INTERIOR 10 A fuse malfunction
•  Open or short circuit in wiring harness between fuse block and rear climate control unit
•  Open or short circuit in wiring harness between rear climate control unit and rear air mix actuator / rear airflow mode actuator
•  Open or short circuit in wiring harness between rear climate control unit and rear air mix actuator position sensor
•  Rear climate control unit connector malfunction or poor connection
•  Rear air mix actuator connector malfunction or poor connection
•  Rear air mix actuator malfunction
•  Rear air mix link malfunction
•  Rear air mix door malfunction
•  Rear climate control unit malfunction
•  Heater hose 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 the coolant sufficiently warmed up?
Yes
Go to the next step.
No
Warm up the engine, then go to Step 24.
2*
INSPECT FUSE
•  Switch the ignition off.
•  Disconnect the negative battery terminal.
•  Remove the ROOM 25 A fuse and INTERIOR 10 A fuse.
•  Is the fuse normal?
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 25 A fuse and front climate control unit / rear 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 REAR CLIMATE CONTROL UNIT) OR ELSEWHERE
•  Disconnect the rear climate control unit connector.
•  Connect the negative battery terminal.
•  Switch the ignition ON (engine off or on).
•  Measure voltage at the following terminal (wiring harness-side).
?  Rear climate control unit terminal V
•  Is the voltage B+?
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 rear 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 REAR A/C UNIT OR REAR AIR MIX ACTUATOR
•  Switch the ignition off.
•  Disconnect the negative battery terminal.
•  Connect the rear climate control unit connector.
•  Connect the negative battery terminal.
•  Switch the ignition ON (engine off or on).
•  Measure and record the voltage at the following terminals (wiring harness-side) when temperature setting to MAX HOT and MAX COLD.
?  Rear climate control unit terminal S
•  Is voltage normal?
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 rear airflow mode at VENT and HEAT.
?  Rear climate control unit terminal Q
•  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).
?  Rear climate control unit terminal W
•  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 rear climate control unit terminal and rear air mix actuator / rear airflow mode 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.
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).
?  Rear climate control unit terminal O
•  Is the voltage below 1.0 V?
Yes
Refer to wiring diagram and inspect for open circuit following.
•  Between rear climate control unit terminal W and junction point to rear actuators (position sensor power supply).
•  Between rear climate control unit terminal O and junction point to rear actuators (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 rear climate control unit terminal and rear air mix actuator / rear airflow mode 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.
8
INSPECT TO SEE WHETHER MALFUNCTION (SHORT TO POWER SUPPLY) IS IN WIRING HARNESS (REAR 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 rear climate control unit terminal and rear 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 REAR CLIMATE CONTROL UNIT CONNECTOR CONNECTION CONDITION
•  Switch the ignition off.
•  Disconnect the negative battery terminal.
•  Inspect the rear climate control unit connector engagement and connection condition.
•  Is the connector normal?
Yes
Go to the next step.
No
Reconnect the rear climate control unit connector properly.
Go to Step 24.
10
INSPECT REAR CLIMATE CONTROL UNIT CONNECTOR TERMINAL CONDITION
•  Disconnect the rear climate control unit connector.
•  Inspect the connector and terminals (corrosion, damage, pin disconnection).
•  Are the connector and terminals normal?
Yes
Go to the next step.
No
Repair/replace the connector or terminal.
Go to Step 24.
11
INSPECT REAR AIR MIX ACTUATOR CONNECTOR CONNECTION CONDITION
•  Inspect the rear air mix actuator connector engagement and connection condition.
•  Is the connector normal?
Yes
Go to the next step.
No
Reconnect the rear air mix actuator connector properly.
Go to Step 24.
12
INSPECT REAR AIR MIX ACTUATOR CONNECTOR TERMINAL CONDITION
•  Disconnect the rear air mix actuator connector.
•  Inspect the connector and terminals (corrosion, damage, pin disconnection).
•  Are the connector and terminals normal?
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 (REAR AIR MIX POSITION SIGNAL) OR ELSEWHERE
•  Inspect continuity between the following terminals (wiring harness-side):
?  Rear climate control unit terminal S—rear air mix actuator terminal B
•  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 rear climate control unit terminal and rear 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 (REAR AIR MIX POSITION SIGNAL) OR ELSEWHERE
•  Inspect for continuity between the following terminals (wiring harness-side) and body ground:
?  Rear climate control unit terminal S
•  Is there continuity?
Yes
Refer to the wiring diagram and verify whether or not there is a common connector between rear climate control unit terminal and rear 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 rear airflow mode actuator (position sensor power supply).
?  Rear air mix actuator terminal A
•  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 rear air mix actuator terminal and junction point to rear airflow mode 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 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 rear airflow mode actuator (position sensor ground).
?  Rear air mix actuator terminal C
•  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 rear air mix actuator terminal and junction point to rear airflow mode 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 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 REAR AIR MIX ACTUATOR OR WIRING HARNESS (LACK OF CONTINUITY BETWEEN REAR CLIMATE CONTROL UNIT AND REAR AIR MIX ACTUATOR)
•  Connect the rear climate control unit connector.
•  Connect the negative battery terminal.
•  Switch the ignition ON (engine off or on).
•  Measure voltage at the following terminals (wiring harness-side).
?  Rear air mix actuator terminal D (HOT motor drive signal)
?  Rear air mix actuator terminal E (COLD motor drive signal)
•  Are voltages normal?
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 REAR CLIMATE CONTROL UNIT AND REAR AIR MIX ACTUATOR) OR ELSEWHERE
•  Switch the ignition off.
•  Disconnect the negative battery terminal.
•  Disconnect the rear climate control unit connector.
•  Inspect for continuity between the following terminals (wiring harness-side).
?  Rear climate control unit terminal G—rear air mix actuator terminal D (HOT motor drive signal)
?  Rear climate control unit terminal E—rear air mix actuator terminal E (COLD motor drive signal)
•  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 rear climate control unit terminal and rear 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 REAR CLIMATE CONTROL UNIT AND REAR AIR MIX ACTUATOR) OR ELSEWHERE
•  Rear climate control unit and rear air mix actuator connectors are disconnected.
•  Connect the negative battery terminal.
•  Switch the ignition ON (engine off or on).
•  Measure voltage at the following terminals (wiring harness-side).
?  Rear climate control unit terminal G (HOT motor drive signal)
?  Rear climate control unit terminal E (COLD 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 rear climate control unit terminal and rear 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 REAR CLIMATE CONTROL UNIT AND REAR AIR MIX ACTUATOR) OR ELSEWHERE
•  Switch the ignition off.
•  Rear climate control unit and rear air mix actuator connectors disconnected.
•  Inspect for continuity between the following terminals (wiring harness-side) and body ground.
?  Rear climate control unit terminal G (HOT motor drive signal)
?  Rear climate control unit terminal E (COLD motor drive signal)
•  Is there continuity?
Yes
Refer to the wiring diagram and verify whether or not there is a common connector between rear climate control unit terminal and rear 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 REAR AIR MIX ACTUATOR
•  Inspect the rear air mix actuator.
•  Is rear air mix actuator normal?
Yes
Replace the rear climate control unit.
(See REAR CLIMATE CONTROL UNIT REMOVAL/INSTALLATION.)
Go to Step 24.
No
Replace the rear air mix actuator.
Then go to Step 24.
(See REAR AIR MIX ACTUATOR REMOVAL/INSTALLATION.)
22
INSPECT REAR AIR MIX LINK
•  Inspect the rear air mix links.
?  Is grease on link?
?  Are links securely and properly installed?
?  Are links free of obstructions and hindrances?
•  Are the above items normal?
Yes
Go to the next step.
No
Apply grease to links.
If any links are damaged. Replace malfunctioning part.
(See REAR A/C UNIT DISASSEMBLY/ASSEMBLY.)
Then go to Step 24.
23
INSPECT REAR A/C UNIT AND REAR AIR MIX DOOR
•  Inspect the rear A/C unit and rear air mix door.
?  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 REAR 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.