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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. (See REAR AIR MIX ACTUATOR INSPECTION.) • 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.