Blend Calibration Fault
NOTE:
After making any repairs, perform BODY VERIFICATION TEST under VERIFICATION TESTS.
- Turn ignition switch to ON position. Using scan tool, read and record all HVAC Diagnostic Trouble Codes (DTC) or fault messages present. Check for any additional DTCs. If no other DTC/fault messages are present, go to next step. Review and record any other DTCs that may exist. Diagnose and repair any active DTCs that exist in other systems.
- Turn ignition switch to OFF position. Remove applicable door actuator for blend (single zone), blend/passenger or zone/driver (dual zone), mode or recirculation doors from front HVAC housing. See Fig 1, Fig 2 and Fig 3 . Disconnect door actuator connector. Attempt to rotate actuator by hand, in both directions. If door actuator rotates in either direction, replace actuator. If door actuator does not rotate by hand, go to appropriate step for actuator. For blend door (single zone), blend/passenger or zone/driver actuators (dual zone), go to next step. For recirculation door actuator, go to step 4. For mode door actuator, go to step 5.
- Place applicable temperature control lever (temperature lever on single zone system, DRIVER or PASS lever on dual zone system) to full cold position. Connect test light between terminals of disconnected blend door actuator harness connector. Turn ignition switch to ON position. While monitoring test light, very slowly sweep applicable temperature lever from full cold to full hot, then very slowly return to full cold position. If test light begins flashing, and remains flashing through entire lever range, go to step 8. If test does not begin to flash, or does not remain flashing through entire lever range, go to step 6.
- Place mode selector to panel, bi-level or floor position. Connect test light between terminals of disconnected recirculation door actuator harness connector. Turn ignition switch to ON position. If recirculation LED is illuminated, press recirculation button to turn it off. While monitoring test light, count number of flashes after each action. Press recirculation button on, test light should flash 4 times. Press recirculation button off, test light should flash 2 times. If test light flashes as described, go to step 8. If test light does not flash as described, go to step 6.
- Turn mode selector dial to panel position, then defrost position, then back to panel position. Connect a test light across terminals of disconnected mode door actuator harness connector. Turn ignition switch to ON position. While monitoring test light, move mode selector dial to first detent after panel position. Test light should flash 4 times. Slowly, move mode selector dial to each detent position between mode symbols until reaching defrost position, while monitoring test light. If test light flashes 4 times in each detent position, go to step 8. If test light does not flash as described, go to next step.
- Turn ignition switch to OFF position. Disconnect HVAC control module C1 connector. See 8. Using DVOM, measure resistance of applicable door driver circuit between HVAC control module C1 connector and disconnected door actuator harness connector. See HVAC CONTROL MODULE CIRCUITS table. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in applicable door driver circuit.
- Turn ignition switch to OFF position. Measure resistance of common door driver circuit between HVAC control module C1 connector terminal No. 9 (Dark Blue/Light Blue wire) and previously disconnected door actuator harness connector. See Fig 4. See AIR CONDITIONING in appropriate SYSTEM WIRING DIAGRAMS article in ELECTRICAL. If resistance is less than 5 ohms, replace HVAC control module. If resistance is 5 ohms or more, repair open in common door driver circuit (Dark Blue/Light Blue wire).
- Inspect HVAC housing plenum and components. Check for any damage, missing components or broken actuator linkage. Check actuator gear and linkage for worn or missing teeth. Check door travel for binding condition or obstructions. Ensure door operation is smooth from stop to stop. Repair any faulty condition found as necessary. If no faults exist with HVAC housing or components, replace door actuator.HVAC CONTROL MODULE CIRCUITS
Terminal No. (Wire Color) (1) Circuit Description HVAC Control Module C1 Connector (2) 1 (Black/Orange) Ground 2 (Dark Blue/Dark Green) Sensor Ground 3 (Light Blue/White) (3) Rear Temperature Feedback Signal 5 (Light Blue/Pink) (3) 5-Volt Supply 6 (Light Blue/Violet) Wiper De-Icer Driver 7 (Dark Blue/Tan) Recirculation Door Driver A 8 (Light Blue/Yellow) (3) Rear Blend Door Driver 9 (Dark Blue/Light Blue) Common Door Driver 10 (White/Violet) PCI Bus 12 (Dark Blue/Dark Green) (3) Rear Temperature Return 13 (Gray/Pink) Ignition Switch (Run) 14 (Orange/Gray) Panel Lamps Driver 15 (Dark Blue/Light Green) Evaporator Temperature Signal 16 (Light Blue/Brown) Blend (Blend/Passenger) Door Driver 17 (Dark Blue/Light Green) Zone/Driver Door Driver 18 (Light Blue/Orange) Mode Door Driver A 19 (Light Blue) (3) Rear Mode Door Driver 20 (Light Blue/Orange) (3) Rear Common Door Driver HVAC Control Module C2 Connector (2) 2 (Dark Blue/Gray) Blower Motor High Driver 3 (Dark Blue/White) Blower Motor M3 Driver 4 (Black/Orange) Ground 5 (Dark Blue/Brown) Blower Motor Low Driver 9 (Dark Blue/Violet) Blower Motor M2 Driver 10 (Dark Blue/Orange) Blower Motor M1 Driver Rear Control/Rear Blower Switch Connector (3)(4) 2 (Black/Dark Green) Ground 4 (Dark Blue/Brown) Rear Blower Motor High 6 (Light Blue/Light Green) Rear Blower Motor Medium 7 (Light Blue/Dark Green) Rear Blower Motor Low 8 (Dark Blue/Orange) Rear Blower Motor Front Control Feed (1) Terminals not listed were not used. (2) For connector view, see Fig 4. (3) If equipped with 3-zone manual A/C-heater system. (4) For connector view, see Fig 5. Courtesy of DAIMLERCHRYSLER CORP.