Rear 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 DTCs. If scan tool displays any additional DTCs, return to HVAC control module DTC/fault list. See DIAGNOSTIC TROUBLE CODE IDENTIFICATION table. Repair additional DTCs set as necessary. If rear calibration message is set, go to next step. If rear mode calibration message is set, go to step 4.
- Turn ignition switch to OFF position. Place rear control blower speed selector at front A/C-heater control panel to REAR position. Set rear zone control panel temperature control switch to full cold setting. Disconnect rear HVAC unit harness connector. See Fig 1. Check rear blend door driver and rear common door driver circuits of wiring harness. Connect a test light between rear HVAC unit harness connector (harness side) terminals No. 7 (Light Blue/Yellow wire) and No. 8 (Light Blue/Orange wire). See Fig 2. Turn ignition switch to ON position. While monitoring test light, very slowly rotate rear zone control panel temperature control switch from full cold to full hot. Then repeat, from full hot to full cold. If test light starts to flash and stay flashing through entire range, in both directions, go to next step. If test light did not flash continuously through entire range in both directions, go to step 7.
- Turn ignition switch to OFF position. Remove test light from previous step. Remove rear blend door actuator from rear HVAC unit. Disconnect rear blend door actuator connector. Using DVOM, measure resistance of Light Blue/Yellow wire between rear blend door actuator harness connector and rear HVAC unit connector terminal No. 7 (component side). Next, measure resistance of Light Blue/Orange wire between blend door actuator harness connector and rear HVAC unit connector terminal No. 8 (component side). If reading for both circuits is less than 5 ohms, go to step 6. If either reading is 5 ohms or more, repair open circuit as necessary.
- Turn ignition switch to OFF position. Place rear control blower speed selector at front A/C-heater control panel to REAR position. Set rear zone control panel temperature control switch to full cold setting. Disconnect rear HVAC unit harness connector. See Fig 1. Check rear mode door driver and rear common door driver circuits of wiring harness. Connect a test light between rear HVAC unit harness connector (harness side) terminals No. 1 (Light Blue wire) and No. 2 (Light Blue/Orange wire). See Fig 2. Turn ignition switch to ON position. While monitoring test light, very slowly rotate rear zone control panel temperature control switch from full cold to full hot. Then repeat, from full hot to full cold. If test light starts to flash and stays flashing through entire range, in both directions, go to next step. If test light did not flash continuously through entire range in both directions, go to step 7.
- Turn ignition switch to OFF position. Remove test light from previous step. Remove rear mode door actuator from rear HVAC unit. Disconnect rear mode door actuator connector. Using DVOM, measure resistance of Light Blue wire between rear mode door actuator harness connector and rear HVAC unit connector terminal No. 1 (component side). Next, measure resistance of Light Blue/Orange wire between mode door actuator harness connector and rear HVAC unit connector terminal No. 2 (component side). If reading for both circuits is less than 5 ohms, go to next step. If either reading is 5 ohms or more, repair open circuit as necessary.
- Turn ignition switch to OFF position. Attempt to rotate suspect door actuator by hand, in both directions. If suspect door actuator turns in either direction, replace faulty door actuator. If door actuator does not rotate when turning it by hand, check rear HVAC housing 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. Repair any faulty condition found as necessary.
- Turn ignition switch to OFF position. Disconnect front HVAC control module C1 connector. Connect rear HVAC unit harness connector, leaving suspect rear blend door actuator and/or rear mode door actuator disconnected. Check rear door driver circuits between HVAC control module and appropriate rear door actuator harness connector. Using DVOM, measure resistance of Light Blue/Yellow wire between HVAC control module C1 connector terminal No. 8 and rear blend door actuator connector. Next, measure resistance of Light Blue wire between HVAC control module C1 connector terminal No. 19 and rear mode door actuator connector. If both readings are less than 5 ohms, go to next step. If either reading is 5 ohms or more, repair open circuit as necessary.
- Check common door driver circuit between HVAC control module and suspect rear door actuator(s). Using a DVOM, measure resistance between HVAC control module C1 connector terminal No. 20 (Light Blue/Orange wire) and appropriate terminal of suspect rear door actuator harness connector. If both readings are less than 5 ohms, replace HVAC control module. If either reading is 5 ohms or more, repair open circuit in rear common door driver circuit as necessary.