NO.9 NO TEMPERATURE CONTROL WITH REAR CLIMATE CONTROL UNIT

BME070300000W11

9

No temperature control with rear climate control unit

DESCRIPTION

• Malfunction in rear A/C unit's air mix system or heater piping.

POSSIBLE CAUSE

• Malfunction in rear air mix actuator's +5 V signal circuit
• Malfunction in rear air mix actuator's potentiometer input signal circuit
• Malfunction in rear air mix actuator's GND signal circuit
• Malfunction in rear air mix actuator's motor drive signal circuit
• Malfunction in rear A/C unit's air mix lever or air mix crank
• Malfunction in rear air mix actuator
• Malfunction in rear A/C unit's air mix door
• Heater piping malfunction

• When performing an asterisked (*) troubleshooting inspection, shake the wiring harness and connectors while doing 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 20.
*2
VERIFY WHETHER MALFUNCTION IS IN REAR AIR MIX ACTUATOR (+5 V SIGNAL) SYSTEM OR ELSEWHERE
• Turn ignition switch to ON position.
• Test voltage at rear air mix actuator connector terminal C (+5 V signal).
• Is voltage approximately B+?
Yes
Go to Step 6.
No
Go to next step.
*3
CHECK FOR CONTINUITY CIRCUIT IN REAR AIR MIX ACTUATOR
• Disconnect rear air mix actuator connector.
• Test voltage at rear air mix actuator terminal C (+5 V signal) on wiring harness side.
• Is voltage approximately 5 V?
Yes
Inspect rear air mix actuator, then go to Step 21.
No
Go to next step.
*4
INSPECT WIRING HARNESS BETWEEN REAR CLIMATE CONTROL UNIT AND REAR AIR MIX ACTUATOR FOR CONTINUITY
• Turn ignition switch to LOCK position.
• Disconnect rear climate control unit connector.
• Is there continuity between rear air mix actuator connector terminal C (+5 V signal) and rear climate control unit connector terminal H?
Yes
Go to next step.
No
Repair wiring harness between rear climate control unit and rear air mix actuator.
*5
VERIFY WHETHER MALFUNCTION IS IN WIRING HARNESS (BETWEEN REAR CLIMATE CONTROL UNIT AND REAR AIR MIX ACTUATOR FOR SHORT TO GROUND) OR REAR CLIMATE CONTROL UNIT
• Is there continuity between rear air mix actuator connector terminal C (+5 V signal) and ground?
Yes
Repair wiring harness between rear climate control unit and rear air mix actuator, then go to Step 21.
No
Replace rear climate control unit, then go to Step 21.
*6
INSPECT WIRING HARNESS BETWEEN REAR CLIMATE CONTROL UNIT AND REAR AIR MIX ACTUATOR FOR CONTINUITY
• Turn ignition switch to LOCK position.
• Disconnect rear climate control unit and rear air mix actuator connector.
• Is there continuity between rear climate control unit connector terminal F and rear air mix actuator connector terminal E?
Yes
Go to next step.
No
Repair wiring harness between rear climate control unit and rear air mix actuator, then go to Step 21.
*7
INSPECT WIRING HARNESS BETWEEN REAR CLIMATE CONTROL UNIT AND REAR AIR MIX ACTUATOR FOR SHORT TO GROUND
• Is there continuity between rear air mix actuator connector terminal E (potentiometer input signal) and ground?
Yes
Repair wiring harness between rear climate control unit and rear air mix actuator, then go to Step 21.
No
Go to next step.
*8
INSPECT WIRING HARNESS BETWEEN REAR CLIMATE CONTROL UNIT AND REAR AIR MIX ACTUATOR FOR SHORT TO B+
• Turn ignition switch to ON position.
• Test voltage at rear air mix actuator terminal E (potentiometer input signal) on wiring harness side.
• Is voltage approximately B+?
Yes
Repair wiring harness between rear climate control unit and rear air mix actuator, then go to Step 21.
No
Go to next step.
*9
INSPECT WIRING HARNESS BETWEEN REAR CLIMATE CONTROL UNIT AND REAR AIR MIX ACTUATOR FOR CONTINUITY
• Is there continuity between rear climate control unit connector terminal E and rear air mix actuator connector terminal A?
Yes
Go to next step.
No
Repair wiring harness between rear climate control unit and rear air mix actuator, then go to Step 21.
*10
INSPECT WIRING HARNESS BETWEEN REAR CLIMATE CONTROL UNIT AND REAR AIR MIX ACTUATOR FOR SHORT TO GROUND
• Is there continuity between rear climate control unit connector terminal E and ground?
Yes
Repair wiring harness between rear climate control unit and rear air mix actuator, then go to Step 21.
No
Go to next step.
*11
INSPECT WIRING HARNESS BETWEEN REAR CLIMATE CONTROL UNIT AND REAR AIR MIX ACTUATOR FOR SHORT TO B+
• Turn ignition switch to ON position.
• Test voltage at rear climate control unit connector terminal E.
• Is voltage approximately B+?
Yes
Repair wiring harness between rear climate control unit and rear air mix actuator, then go to Step 21.
No
Go to next step.
*12
INSPECT WIRING HARNESS BETWEEN REAR CLIMATE CONTROL UNIT AND REAR AIR MIX ACTUATOR FOR CONTINUITY
• Is there continuity between following rear climate control unit connector terminals and rear air mix actuator connector terminals (motor drive signal)?
- Terminal A-Terminal G
- Terminal B-Terminal F
Yes
Go to next step.
No
Repair wiring harness between rear climate control unit and rear air mix actuator, then go to Step 21.
*13
INSPECT WIRING HARNESS BETWEEN REAR CLIMATE CONTROL UNIT AND REAR AIR MIX ACTUATOR FOR SHORT TO GROUND
• Is there continuity between following rear climate control unit connector terminals and ground?
- Terminal A
- Terminal B
Yes
Repair wiring harness between rear climate control unit and rear air mix actuator, then go to Step 21.
No
Go to next step.
*14
INSPECT WIRING HARNESS BETWEEN REAR CLIMATE CONTROL UNIT AND REAR AIR MIX ACTUATOR FOR SHORT TO B+
• Turn ignition switch to ON position.
• Test voltage at following rear air mix actuator terminals (motor drive signal) on wiring harness side.
- Terminal F-Terminal G
- Terminal B-Terminal F
• Is voltage approximately B+?
Yes
Repair wiring harness between rear climate control unit and rear air mix actuator, then go to Step 21.
No
Go to next step.
15
INSPECT REAR A/C UNIT'S REAR AIR MIX ACTUATOR
• Remove rear A/C unit's rear air mix actuator.
• Inspect rear A/C unit's air mix lever and crank as follows.
- Is there grease on lever and crank?
- Are lever and crank properly and securely positioned?
• Are above items all okay?
Yes
Go to next step.
No
Apply grease or install lever and crank securely in their proper positions, then go to Step 21.
16
VERIFY WHETHER MALFUNCTION IS IN REAR AIR MIX ACTUATOR OR ELSEWHERE
• Turn ignition switch to ON position.
• Set rear main fan switch at third position.
• Does temperature of discharged air change smoothly when air mix crank is operated by hand?
Yes
Go to next step.
No
Go to Step 18.
17
INSPECT REAR AIR MIX ACTUATOR
• Inspect rear air mix actuator.
• Is it okay?
Yes
Go to next step.
No
Replace rear air mix actuator, then go to Step 21.
18
INSPECT REAR A/C UNIT
• Is there any foreign material or obstructions in rear A/C unit's air mix door?
Yes
Remove obstruction, then go to Step 21.
No
Go to next step.
19
INSPECT REAR A/C UNIT'S AIR MIX DOOR
• Inspect rear A/C unit's air mix door as follows.
- Is air mix door free of cracks and damage?
- Is air mix door securely and properly installed?
• Are above items okay?
Yes
Go to next step.
No
Replace air mix door or install air mix door securely in proper position, then go to Step 21.
20
INSPECT HEATER LINES
• Inspect heater lines as follows.
- Is heater piping free of damage and cracks?
- Are heater piping connections free of engine coolant leakage?
- Are heater piping connections loose?
- Are heater piping installation points on rear A/C unit free of engine coolant leakage?
• Are above items okay?
Yes
Replace rear climate control unit, then go to next step. If heater piping connections is loosened, tighten connections to specified torque.
No
Repair or replace heater piping, then go to next step.
21
VERIFY THAT MALFUNCTION SYMPTOM OCCURS AFTER REPAIR
• Does unit operate in every temperature setting?
Yes
Troubleshooting completed. Explain repairs to customer.
No
Recheck malfunction symptoms, then repeat from Step 1 if malfunction recurs.