HVAC System - Automatic: Other GMC Envoy I

Blower Motor Control Knob

When blower motor control knob is set to AUTO mode, blower motor speed is determined by the blower control module and its network of sensors. When blower motor control knob is rotated from AUTO to OFF position and beyond, blower control module switches to manual mode. In manual mode, 13 speeds can be selected with the blower motor control knob. Blower motor speed remains the same until a new speed is selected by operator. When blower motor control knob is OFF, some air will enter vehicle when vehicle is moving. (Scheme 4)

Temperature Control Knob

In-vehicle temperature can be set between 66°F (19°C) and 82°F (28°C) When temperature control knob is rotated left (Blue half of indicator) past 66°F (19°C) system will be in full cool operation. When temperature control knob is rotated right (Red half of indicator) past 82°F (28°C), system will be in full heat operation. (Scheme 4)

Scheme 4

Mode Select Knob

Different modes of operation can be selected: AUTO, panel (vents), floor/panel, floor, floor/windshield and front defrost. (Scheme 4)

AUTO (Automatic) Mode

The A/C-heater control module evaluates input of sensors and determines weather floor, floor/panel or panel mode is required. The A/C-heater control module then commands appropriate actuators to open doors to predetermined outlets. A/C-heater control module also commands either fresh or recirculated air to be used in AUTO mode of operation.

Panel Mode

The A/C-heater control module commands actuators to close defrost door, position air inlet door for outside air to be pulled in and position A/C door so air is discharged through panel vents.

Floor/Panel Mode

The A/C-heater control module commands actuators to close defrost door, position air inlet door for outside air to be pulled in and position A/C door so air is discharged through floor outlets and panel vents.

Note. In panel, floor/panel, floor, floor/windshield, front/defrost mode, A/C compressor comes on if outside temperature is above 43°F (6°C) and maintains an evaporator core temperature of around 33°F (1°C) as long as the A/C button is not depressed.

Floor Mode

The A/C-heater control module commands actuators to close defrost door, position air inlet door for outside air to be pulled in and position A/C door so air is discharged through floor vents. In this mode, a small amount of air will be discharged to the windshield outlets.

Floor/Windshield Mode

The A/C-heater control module commands actuators to open defrost door, position air inlet door for outside air to be pulled in and position A/C door so air is discharged through floor outlets. The blower pulls outside air in and directs it out floor and windshield outlets.

Front Defrost Mode

The A/C-heater control module commands actuators to open defrost door, position air inlet door for outside air to be pulled in and position A/C door so some air is discharged through floor outlets. In this mode, A/C compressor cannot be turned off and recirculation setting cannot be selected.

Recirculation Mode

When recirculated air switch is pressed, the A/C-heater control module commands actuator to close air inlet door to outside air. Recirculation mode is available in panel/floor, panel and floor modes. Recirculation mode is not allowed in front defrost or floor/windshield modes because windshield fogging might occur.

Fresh Air Mode

This mode allows fresh outside air to enter passenger compartment when fresh air switch is pressed. (Scheme 4)

ACTUATORS

There are 6 actuators used to control the automatic climate control system. One electronic air mix door actuator, one vacuum controlled inlet door actuator and 4 vacuum controlled mode door actuators. The electronic air mix door actuator contains a feedback potentiometer. The feedback potentiometer signals A/C-heater control module with air mix door position.

PULSE WIDTH MODULATING DRIVE MOTOR

In AUTO mode, A/C-heater control module determines appropriate blower motor speed by analyzing information from various sensors, including engine coolant temperature sensor and vehicle speed sensor, and sends Pulse Width Modulated (PWM) voltage to the Pulse Width Modulating Drive Motor (PWMDM). Drive motor is located at blower motor assembly, connected directly to blower motor.

The PWMDM receives PWM voltage from A/C-heater control module and powers the blower motor accordingly. To increase or decrease blower motor speed, the A/C-heater control module varies PWM voltage. A higher PWM voltage increases blower motor speed, lower PWM voltage decreases blower motor speed. In manual mode, blower motor operates at speed selected on blower motor increase/decrease knob.

A/C Pressure Sensor

Located on the high side of the A/C compressor suction/discharge hose assembly, it monitors A/C system pressure to engage and disengage the A/C compressor clutch.

Passenger Compartment (Inside) Air Temperature Sensor

This temperature sensitive resistor (thermistor) monitors in-vehicle temperature to accurately control and maintain set temperature. Higher temperature lowers resistance of sensor, lower temperature raises resistance of sensor.

Inside air temperature sensor has a dedicated fan to pull interior air past it for precise metering of in-vehicle temperature. Sensor is located above drivers door under roof trim molding inside the in-vehicle air temperature sensor housing.

Upper & Lower Outlet Temperature Sensors

These sensors are used by the A/C-heater control module to monitor discharge temperatures from floor and panel outlets. Upper sensor is located in center A/C-heater duct, above radio. Lower sensor is in lower outlet duct.

Ambient (Outside) Air Temperature Sensor

This thermistor is used by A/C-heater control module to determine command signals for automatic climate control system. Ambient air temperature sensor is located on right side of radiator support baffle.

Solar Sensor

Light-sensitive photo-diode used to monitor heat load of sun on vehicle. A/C-heater control module uses solar sensor information to regulate the automatic climate control for increased solar heat. Solar sensor is located in the defrost grille on center of dash.

ACTUATOR CHECK

Note. This check must be performed every time the electronic actuator is removed for repair or replaced.

Electronic Actuator

1. Turn ignition switch to OFF position. Remove RDO/BATT fuse for 10 seconds.
2. Install RDO/BATT fuse. Turn ignition switch to ON position. Electronic actuator should cycle air mix door through hot and cold positions.

Vacuum Actuators

Install scan tool. Operate A/C-heater control module through all blower fan speeds and all air distribution modes. Check readings on scan tool against vacuum actuator check table. (Scheme 5)

Scheme 5

BLOWER MOTOR CONTROL DOES NOT OPERATE PROPERLY

1. If blower motor fails to operate in any switch position, go to next step. If blower motor operates in any switch position, go to step 21).
2. Check HVAC fuse. If fuse is blown, go to next step. If fuse is okay, go to step 6).
3. Disconnect Pulse Width Modulating Drive Motor (PWMDM) connector. Remove HVAC fuse and connect test light between terminals "A" and "B" of HVAC fuse cavity. If test light comes on, go to next step. If test light does not come on, go to step 5).
4. Repair short to ground in Orange wire between PWMDM connector terminal "B" and HVAC fuse in underhood fuse block. Recheck operation of blower motor control.
5. Replace HVAC fuse. Recheck operation of blower motor control. If blower motor does not operate properly, go to step 11).
6. Disconnect PWMDM connector. Connect test light between terminals "A" and "B" of PWMDM connector. If test light comes on, go to next step. If test light does not come on, go to step 8).
7. Reconnect PWMDM connector. Turn ignition switch to ON position. Set blower motor speed control knob to mid-range position. Using a DVOM, backprobe A/C-heater control module connector terminal C16. If DVOM indicates 2-4 volts, go to step 11). If DVOM indicates other than 2-4 volts, go to step 14).
8. Connect test light to PWMDM connector terminal "B" and battery ground. If test light comes on, go to step 10). If test light does not come on, go to next step.
9. Repair open in Orange wire between PWMDM connector terminal "B" and HVAC fuse in underhood fuse block. Recheck operation of blower motor control.
10. Repair open in Black wire between PWMDM connector terminal "A" and ground. Recheck operation of blower motor control. CAUTION: Use wire of gauge suitable for current needed to power blower motor.
11. Disconnect PWMDM connector. Disconnect blower motor from PWMDM. Connect jumper wire from PWMDM connector terminal "B" to blower motor Red terminal. Connect jumper wire from PWMDM connector terminal "A" to blower motor Black terminal. If blower motor operates at maximum speed, go to step 13). If blower motor does not operate at maximum speed, go to next step.
12. Replace blower motor. Recheck operation of blower motor control.
13. Replace PWMDM. Recheck operation of blower motor control.
14. If DVOM indicates 0 volts, go to next step. If DVOM indicates other than 0 volts, go to step 25).
15. Turn ignition to OFF position. Disconnect A/C-heater control module connector. Disconnect PWMDM connector. Connect a test light between terminals "A" and "C" of PWMDM connector. If test light glows, go to next step. If test light does not glow, go to step 26).
16. Repair short to ground in Purple/White wire between terminal "C" of PWMDM connector and terminal C16 of A/C-heater control module connector. Recheck operation of blower motor control.
17. Connect test light between terminals "A" and "C" of PWMDM connector. If test light comes on, go to next step. If test light does not come on, go to step 19).
18. Repair short to battery voltage in Purple/White wire between terminal "C" of PWMDM connector and terminal C16 of A/C-heater control module connector. Recheck operation of blower motor control.
19. Replace PWMDM. Recheck operation of blower motor control. If blower does not operate properly, go to next step.
20. Replace A/C-heater control module. Recheck operation of blower motor control.
21. If symptom is blower motor runs at maximum speed constantly, go to next step. If symptom is other than listed, go to step 20).
22. Turn ignition to OFF position. Disconnect A/C-heater control module connector. If blower motor stops running at maximum speed, go to step 20). If blower motor continues to operate at maximum speed, go to next step.
23. Replace PWMDM. Recheck operation of blower motor control.
24. If symptom is intermittent operation of blower motor or erratic operation of blower motor when changing speed with blower select switch, go to step 20). If symptom is other than listed, go to «A/C-HEATER CONTROL MODULE DIAGNOSTIC SYSTEM CHECK»(ref-40623-S06053354452001011200000) .
25. If DVOM indicates battery voltage, go to step 17). If DVOM indicates other than battery voltage, go to step 28).
26. Connect jumper wire between terminals "A" and "C" of PWMDM connector. Connect DVOM to A/C-heater control module connector terminal C16 and battery ground. If DVOM indicates less than 5 ohms resistance, go to step 28). If resistance is greater than 5 ohms, go to next step.
27. Repair open in Purple/White wire between terminal "C" of PWMDM connector and terminal C16 of A/C-heater control module connector. Recheck operation of blower motor control.
28. Replace PWMDM. Recheck operation of blower motor control. If blower does not operate properly, go to step 20).

Scheme 6

1. Check for A/C-heater control module DTCs. See procedures in «RETRIEVING DIAGNOSTIC TROUBLE CODES»(ref-40623-S12217572702001011200000) under TESTING. If DTCs are present, go to appropriate DTC under TESTING. If no DTCs are present, go to next step.
2. Operate A/C-heater control module and check readings on scan tool, check results against vacuum actuator check table. (Scheme 5) If scan tool data matches table, go to next step. If results are different, go to step 9).
3. Check for open in Brown wire between A/C-heater control module connector terminal C6 and HVAC fuse. If wire is open, repair wire and recheck operation of air distribution system. If wire is okay, go to next step.
4. Perform select solenoid test using scan tool. Cycle solenoids 1 through 5. Locate HVAC solenoid assembly. (Scheme 6) Place hand on each solenoid while energizing it with scan tool. If all solenoids energize as commanded, go to step 6). If one or more solenoids fail to energize, go to next step.
5. Check for open, short to ground or short to battery voltage in corresponding wire for solenoid, between A/C-heater control module connector and HVAC solenoid assembly connector. If one or more circuits were repaired, recheck operation of air distribution system. If no repair was needed, go to step 8).
6. Start engine, apply parking brake. Check for loose, pinched or broken vacuum lines. If repair was made, recheck operation of air distribution system. If no repair was needed, go to next step.
7. Install vacuum gauge to vacuum line for inoperative actuator. Cycle solenoid for actuator. If vacuum is present, go to step 10). If no vacuum is present, go to next step.
8. Replace HVAC solenoid assembly. Recheck operation of air distribution system.
9. Replace A/C-heater control module. Recheck operation of air distribution system.
10. Replace defective vacuum actuator. Recheck operation of air distribution system.

A/C SYSTEM PERFORMANCE

1. Park vehicle out of direct sunlight. Start engine and allow to idle. Set A/C controls to outside air, panel (vent) mode, full cold, and A/C button on. Set blower/fan on high speed and close windows.
2. Operate system for 8-10 minutes to allow system to stabilize. Insert thermometer in center vent, and measure outlet temperature. Outlet temperature must be 36-60°F (2-15°C) at center vent, with low/high side pressures within specification. Refer to «A/C PERFORMANCE PRESSURE SPECIFICATIONS»(ref-40623-S10050266612001011200000) .

A/C PERFORMANCE PRESSURE SPECIFICATIONS

CODE B0160: AMBIENT (OUTSIDE) AIR TEMPERATURE SENSOR CIRCUIT LOW

1. Turn ignition switch to OFF position. Disconnect sensor. Using a DVOM, measure resistance across sensor terminals "A" and "B". See «AMBIENT/PASSENGER COMPARTMENT TEMPERATURE SENSOR RESISTANCE»(ref-40623-S24338038492001011200000) table. If resistance is in specified range for temperature, go to next step. If resistance is not as specified, go to step 5).
2. Disconnect A/C-heater control module. With DVOM, check for short to ground at terminal D2 (Dark Green/White wire) of A/C-heater control module connector. If continuity is indicated, go to step 4). If continuity is not indicated, go to next step.
3. Reconnect sensor. Reconnect A/C-heater control module connector. Turn ignition switch to ON position. Clear A/C-heater system DTCs. See «CLEARING TROUBLE CODES»(ref-40623-S27889148062001011200000) . Operate A/C-heater system. If DTC resets, go to step 6). If DTC does not reset, check connections to sensor and A/C-heater control module.
4. Repair short to ground in Dark Green/White wire between A/C-heater control module connector terminal D2 and ambient temperature sensor.
5. Replace ambient temperature sensor.
6. Replace A/C-heater control module.

CODE B0161: AMBIENT (OUTSIDE) AIR TEMPERATURE SENSOR CIRCUIT HIGH

1. Turn ignition switch to OFF position. Disconnect sensor. Using a DVOM, measure resistance across sensor terminals "A" and "B". See «AMBIENT/PASSENGER COMPARTMENT TEMPERATURE SENSOR RESISTANCE»(ref-40623-S24338038492001011200000) . If resistance is in specified range for temperature, go to next step. If resistance is not as specified, go to step 5).
2. Turn ignition switch to ON position. With a DVOM, measure voltage at terminal "B" (Dark Green/White wire) of ambient temperature sensor. If DVOM indicates battery voltage, go to next step. If DVOM indicates other than battery voltage, go to step 9).
3. Check Dark Green/White wire between A/C-heater control module and ambient temperature sensor for short to battery voltage and repair. If wire is okay, go to step 8).
4. With a DVOM, check for continuity to ground at terminal "A" of ambient temperature sensor connector. If continuity is indicated, go to step 7). If continuity is not indicated, go to step 6).
5. Replace ambient temperature sensor.
6. Check Black wire after terminal "A" of ambient temperature sensor connector for an open and repair. If no open was found, go to step 8).
7. Turn ignition switch to OFF position. Reconnect sensor. Turn ignition switch to ON position. Clear A/C-heater system DTCs. See «CLEARING TROUBLE CODES»(ref-40623-S27889148062001011200000) . Operate A/C-heater system. If DTC resets, go to next step. If DTC does not reset, check connections to sensor and A/C-heater control module.
8. Replace A/C-heater control module.
9. Using a DVOM, check voltage at terminal "B" of ambient temperature sensor connector. If DVOM indicates between 4-6 volts, go to step 4). If DVOM does not indicate 4-6 volts, go to next step.
10. Check for open Dark Green/White wire between A/C-heater control module and ambient temperature sensor. Repair as necessary. If wire is okay, go to step 8).

CODE B0165: PASSENGER COMPARTMENT TEMPERATURE SENSOR NO. 1 CIRCUIT LOW

1. Turn ignition switch to OFF position. Disconnect sensor. Use a DVOM to measure resistance across sensor terminals "A" and "B". See «AMBIENT/PASSENGER COMPARTMENT TEMPERATURE SENSOR RESISTANCE»(ref-40623-S24338038492001011200000) . If resistance is in specified range for temperature, go to next step. If resistance is not as specified, go to step 5).
2. Disconnect A/C-heater control module connector. With a DVOM, check for continuity to ground at terminal D1 (Dark Green wire) of A/C-heater control module connector. If continuity is indicated, go to step 4). If continuity is not indicated, go to next step.
3. Turn ignition switch to OFF position. Reconnect sensor and A/C-heater control module connectors. Turn ignition to ON position. Clear A/C-heater system DTCs. See «CLEARING TROUBLE CODES»(ref-40623-S27889148062001011200000) under TESTING. Operate A/C-heater system. If DTC resets, go to step 6). If DTC does not reset, check connections to sensor and A/C-heater control module.
4. Repair short to ground in Dark Green wire between terminal "A" of passenger compartment temperature sensor and terminal D1 of A/C-heater control module connector.
5. Replace sensor.
6. Replace A/C-heater control module.

CODE B0166: PASSENGER COMPARTMENT TEMPERATURE SENSOR NO. 1 CIRCUIT HIGH

1. Turn ignition switch to OFF position. Disconnect sensor. Use a DVOM to measure resistance across sensor terminals "A" and "B". See «AMBIENT/PASSENGER COMPARTMENT TEMPERATURE SENSOR RESISTANCE»(ref-40623-S24338038492001011200000) . If resistance is in specified range for temperature, go to next step. If resistance is not as specified, go to step 5).
2. Turn ignition switch to ON position. With a DVOM, check voltage at terminal "A" of sensor. If battery voltage exists, go to next step. If battery voltage does not exist, go to step 9).
3. Check Dark Green wire between terminal "A" of passenger compartment temperature sensor and terminal D1 of A/C-heater control module connector for short to battery voltage and repair. If wire is okay, go to step 8).
4. Check for continuity to ground at terminal "D" (Black wire) of sensor connector. If continuity is indicated, go to step 7). If continuity is not indicated, go to step 6).
5. Replace sensor.
6. Check Black wire after terminal "D" of sensor connector for an open and repair. If no repair was needed, go to step 8).
7. Turn ignition switch to OFF position. Reconnect sensor. Turn ignition switch to ON position. Clear A/C-heater system DTCs. See «CLEARING TROUBLE CODES»(ref-40623-S27889148062001011200000) under TESTING. Operate A/C-heater system. If DTC resets, go to next step. If DTC does not reset, check connections to sensor and A/C-heater control module.
8. Replace A/C-heater control module.
9. Using a DVOM, check voltage at terminal "A" of passenger compartment ambient temperature sensor connector. If DVOM indicates between 4-6 volts, go to step 4). If DVOM does not indicate 4-6 volts, go to next step.
10. Check Dark Green wire between terminal "A" of passenger compartment temperature sensor and terminal D1 of A/C-heater control module connector for open and repair. If wire is okay, go to step 8).

AMBIENT/PASSENGER COMPARTMENT TEMPERATURE SENSOR RESISTANCE

CODE B0175: OUTLET AIR TEMPERATURE SENSOR NO. 1 (UPPER) CIRCUIT LOW

1. Turn ignition switch to OFF position. Disconnect sensor. Use a DVOM to measure resistance across sensor terminals "A" and "B". See «UPPER/LOWER OUTLET TEMPERATURE SENSOR RESISTANCE»(ref-40623-S31836344932001011200000) . If resistance is in specified range for temperature, go to next step. If resistance is not as specified, go to step 5).
2. Disconnect A/C-heater control module connector. With a DVOM, check for continuity to ground at terminal C2 (Brown wire) of A/C-heater control module connector. If continuity is indicated, go to step 4). If continuity is not indicated, go to next step.
3. Turn ignition switch to OFF position. Reconnect sensor and A/C-heater control module connectors. Turn ignition switch to ON position. Clear A/C-heater system DTCs. See «CLEARING TROUBLE CODES»(ref-40623-S27889148062001011200000) under TESTING. Operate A/C-heater system. If trouble code resets, go to step 8). If trouble code does not reset, check connections to sensor and A/C-heater control module.
4. Repair short to ground in Brown wire between upper output temperature sensor connector terminal "A" and A/C-heater control module connector terminal C2.
5. Replace sensor.
6. Replace A/C-heater control module.

CODE B0176: OUTLET AIR TEMPERATURE SENSOR NO. 1 (UPPER) CIRCUIT HIGH

1. Turn ignition switch to OFF position. Disconnect sensor. Use a DVOM to measure resistance across sensor terminals "A" and "B". See «UPPER/LOWER OUTLET TEMPERATURE SENSOR RESISTANCE»(ref-40623-S31836344932001011200000) . If resistance is in specified range for temperature, go to next step. If resistance is not as specified, go to step 5).
2. Turn ignition switch to ON position. With a DVOM, check voltage at terminal "A" of sensor. If battery voltage exists, go to next step. If battery voltage does not exist, go to step 9).
3. With a DVOM, check for short to battery voltage in Brown wire between upper output temperature sensor connector terminal "A" and A/C-heater control module connector terminal C2. If wire is okay, go to step 8).
4. With a DVOM, check for continuity to ground at terminal "B" (Black wire) of sensor connector. If continuity is indicated, go to step 7). If continuity is not indicated, go to step 6).
5. Replace sensor.
6. Check Black wire after terminal "B" of sensor connector for an open and repair. If no repair was needed, go to step 8).
7. Turn ignition switch to OFF position. Reconnect sensor. Turn ignition switch to ON position. Clear A/C-heater system DTCs. See «CLEARING TROUBLE CODES»(ref-40623-S27889148062001011200000) under TESTING. Operate A/C-heater system. If DTC resets, go to next step. If DTC does not reset, check connections to sensor and A/C-heater control module.
8. Replace A/C-heater control module.
9. Using a DVOM, check voltage at terminal "A" of upper output air temperature sensor connector. If DVOM indicates between 4-6 volts, go to step 4). If DVOM does not indicate 4-6 volts, go to next step.
10. Check for open Brown wire between terminal "A" of sensor and terminal C2 of A/C-heater control module connector. Repair as necessary. If wire is okay, go to step 8).

CODE B0180: OUTLET AIR TEMPERATURE SENSOR NO. 2 (LOWER) CIRCUIT LOW

1. Turn ignition switch to OFF position. Disconnect sensor. Use a DVOM to measure resistance across sensor terminals "A" and "B". See «UPPER/LOWER OUTLET TEMPERATURE SENSOR RESISTANCE»(ref-40623-S31836344932001011200000) . If resistance is in specified range for temperature, go to next step. If resistance is not as specified, go to step 5).
2. Disconnect A/C-heater control module connector. With a DVOM, check for continuity to ground at terminal C3 (Light Green wire) of A/C-heater control module connector. If continuity is indicated, go to step 4). If continuity is not indicated, go to next step.
3. Turn ignition switch to OFF position. Reconnect sensor and A/C-heater control module connectors. Turn ignition switch to ON position. Clear A/C-heater system DTCs. See «CLEARING TROUBLE CODES»(ref-40623-S27889148062001011200000) under TESTING. Operate A/C-heater system. If trouble code resets, go to step 8). If trouble code does not reset, check connections to sensor and A/C-heater control module.
4. Repair short to ground in Light Green wire between sensor connector terminal "A" and A/C-heater control module connector terminal C3.
5. Replace sensor.
6. Replace A/C-heater control module.

CODE B0181: OUTLET AIR TEMPERATURE SENSOR NO. 2 (LOWER) CIRCUIT HIGH

1. Turn ignition switch to OFF position. Disconnect sensor. Use a DVOM to measure resistance across sensor terminals "A" and "B". See «UPPER/LOWER OUTLET TEMPERATURE SENSOR RESISTANCE»(ref-40623-S31836344932001011200000) . If resistance is in specified range for temperature, go to next step. If resistance is not as specified, go to step 5).
2. Turn ignition switch to ON position. With a DVOM, check voltage at terminal "A" of sensor. If battery voltage exists, go to next step. If battery voltage does not exist, go to step 9).
3. Check for short to battery voltage in Light Green wire between lower output temperature sensor connector terminal "A" and A/C-heater control module connector terminal C3. If wire is okay, go to step 8).
4. With a DVOM, check for continuity to ground at terminal "B" (Black wire) of sensor connector. If continuity is indicated, go to step 7). If continuity is not indicated, go to step 6).
5. Replace sensor.
6. Check for open Black wire to terminal "B" of sensor connector. Repair as necessary. If wire is okay, go to step 8).
7. Turn ignition switch to OFF position. Reconnect sensor. Turn ignition switch to ON position. Clear A/C-heater system DTCs. See «CLEARING TROUBLE CODES»(ref-40623-S27889148062001011200000) under TESTING. Operate A/C-heater system. If DTC resets, go to next step. If DTC does not reset, check connections to sensor and A/C-heater control module.
8. Replace A/C-heater control module.
9. Using a DVOM, check voltage at terminal "A" of upper output air temperature sensor connector. If DVOM indicates between 4-6 volts, go to step 4). If DVOM does not indicate 4-6 volts, go to next step.
10. Check for open Light Green wire between terminal "A" of sensor and terminal C3 of A/C-heater control module connector. Repair as necessary. If wire is okay, go to step 8).

UPPER/LOWER OUTLET TEMPERATURE SENSOR RESISTANCE

CODE B0185: SOLAR LOAD SENSOR CIRCUIT LOW

1. Turn ignition switch to OFF position. Disconnect solar load sensor. Disconnect A/C-heater control module connector. With a DVOM, check for continuity to ground at terminal C1 (Light Blue/Black wire) of A/C-heater control module connector. If continuity is indicated, go to step 3). If continuity is not indicated, go to next step.
2. Reconnect sensor and A/C-heater control module connectors. Turn ignition switch to ON position. Cover solar load sensor from light. Read solar load sensor counts on scan tool. Correct reading is 10 counts or less. If sensor stays at or around 20 counts, go to step 4). If counts are other than specified, go to step 5).
3. Repair short to ground in Light Blue wire between solar load sensor connector terminal "A" and A/C-heater control module connector terminal C1.
4. Replace sensor.
5. Clear A/C-heater system DTCs. See CLEARING TROUBLE CODES under TESTING. Operate A/C-heater system. If DTC resets, go to next step. If DTC does not reset, check connections to sensor and A/C-heater control module.
6. Replace A/C-heater control module.

CODE B0186: SOLAR LOAD SENSOR CIRCUIT HIGH

1. Turn ignition switch to OFF position. Disconnect solar load sensor. With a DVOM, check voltage at terminal "A" of sensor connector. If battery voltage exists, go to next step. If battery voltage does not exist, go to step 9).
2. Check Light Blue wire between solar load sensor connector terminal "A" and A/C-heater control module connector terminal C1 for short to battery voltage and repair. If wire is okay, go to step 8).
3. With a DVOM, check for continuity to ground at terminal "B" of sensor connector. If continuity is indicated, go to next step. If continuity is not indicated, go to step 6).
4. Turn ignition switch to OFF position. Reconnect solar load sensor. Turn ignition to ON position. Use incandescent shop light to shine on sun load sensor. If solar load counts on scan tool read above 250, go to next step. If counts are below 250, go to step 7).
5. Replace sensor.
6. Repair open in Black wire between solar sensor connector terminal "B" and A/C-heater control module connector terminal D9. If wire is okay, go to step 8).
7. Turn ignition switch to OFF position. Reconnect sensor. Turn ignition switch to ON position. Clear A/C-heater system DTCs. See «CLEARING TROUBLE CODES»(ref-40623-S27889148062001011200000) under TESTING. Operate A/C-heater system. If DTC resets, go to next step. If DTC does not reset, check connections to sensor and A/C-heater control module.
8. Replace A/C-heater control module.
9. Using a DVOM, check voltage at terminal "A" of solar load sensor connector. If DVOM indicates between 4-6 volts, go to step 5). If DVOM does not indicate 4-6 volts, go to next step.
10. Check for open in Light Blue wire between solar load sensor connector terminal "A" and A/C-heater control module connector terminal C1 and repair. If wire is okay, go to step 8).

CODE B0408: TEMPERATURE CONTROL NO. 1 (MAIN) CIRCUIT MALFUNCTION

1. Install the scan tool. Turn ON the ignition, with the engine OFF. With the scan tool, check DTCs. If the scan tool indicates that DTC B0415 or B0416 set along with B0408, see appropriate DTC test. If the scan tool does not indicate that DTC B0415 or B0416 set along with B0408, go to next step.
2. Install the scan tool. Turn ON the ignition, with the engine OFF. With the scan tool, observe the Air Mix Door Commanded data parameter and the Air Mix Door Actual data parameter in the Heater and Air Conditioning Data Display. If the scan tool indicates that the Air Mix Door Commanded data parameter is within 0-3 counts of the Air Mix Door Actual data parameter, check normal operating range. Normal operating range is 40 Counts to 200 Counts. If out of this range check for binding, misalignment, or broken air temperature door. If the scan tool does not indicate that the Air Mix Door Commanded data parameter is within 0-3 counts of the Air Mix Door Actual data parameter, go to next step.
3. With the scan tool, command the air temperature actuator from HOT (Off) to COLD (On). With the scan tool, observe the Air Mix Door Actual parameter in the Heater and Air Condition Data Display. If the Air Mix Door Actual data parameter changes at all, go to step 9. If the Air Mix Door Actual data parameter does not change at all, go to next step.
4. Test the ignition 3 voltage circuit of the air temperature actuator for an open or a high resistance. See «WIRING DIAGRAMS»(ref-40623-S33728165612001011200000) . If you find and correct the condition, go to step 14. If you do not find and correct the condition, go to next step.
5. Test the 5 volt reference circuit of the air temperature actuator for an open, high resistance, short to ground or short to voltage. See «WIRING DIAGRAMS»(ref-40623-S33728165612001011200000) . If you find and correct the condition, go to step 14. If you did not find and correct the condition, go to next step.
6. Test the air temperature door control circuit of the air temperature actuator for an open, high resistance, short to ground or short to voltage. See «WIRING DIAGRAMS»(ref-40623-S33728165612001011200000) . If you find and correct the condition, go to step 14. If you did not find and correct the condition, go to next step.
7. Test the air temperature actuator ground for open, or high resistance. See «WIRING DIAGRAMS»(ref-40623-S33728165612001011200000) . If you find and correct the condition, go to step 14. If you did not find and correct the condition, go to next step.
8. Turn ON the ignition, with the engine OFF. With the scan tool, observe the Air Mix Door Actual data parameter in the Heater and Air Condition Data Display. Connect a 3 amp fused jumper wire between the air temperature door control circuit and the 5 volt reference circuit of the air temperature actuator (drives the actuator full COOL). Remove and reconnect the jumper wire between the air temperature door control circuit and the ground circuit of the air temperature actuator (drives the actuator full HOT). If the air temperature actuator drive shaft rotates and the counts change, go to step 11. If the air temperature actuator drive shaft does not rotate and the counts don't change, go to next step.
9. Inspect the air temperature door and the air temperature actuator for the following: Incorrectly installed air temperature actuator. Broken or binding linkages or air temperature door. Obstruction that prevents the air temperature door from operating within it's full range of motion. If you find and correct the condition, go to step 14. If you did not find and correct the condition, go to next step.
10. Inspect for poor connections at the harness connector of the air temperature actuator. If you find and correct the condition, go to step 14. If you did not find and correct the condition, go to step 12.
11. Inspect for poor connections at the harness connector of the HVAC control module. If you find and correct the condition, go to step 14. If you did not find and correct the condition, go to step 13.
12. Replace the air temperature actuator. Refer to «ELECTRONIC AIR MIX DOOR ACTUATOR»(ref-40623-S26525955022001011200000) . Go to step 14.
13. Replace the HVAC control module. Refer to «A/C-HEATER CONTROL MODULE»(ref-40623-S38613819842001011200000) . Go to Step 14.
14. Use the scan tool in order to clear the DTCs. Operate the vehicle within the conditions for running the DTC. If the DTC resets, go to step 1. If the DTC does not reset, the system is OK.

CODE B0415: TEMPERATURE CONTROL NO. 1 CIRCUIT LOW (FEEDBACK CIRCUIT LOW)

1. Turn ignition switch to OFF position. Using a DVOM, backprobe A/C-heater control module connector. Check for short to ground at A/C-heater control module connector terminals C4 and D5. If DVOM indicates continuity on either circuit, go to next step. If DVOM does not indicate continuity on either circuit, go to step 6).
2. Disconnect electronic actuator connector. Recheck for short to ground between A/C-heater control module connector terminals C4 and D5. If DVOM indicates continuity, go to next step. If DVOM does not indicate continuity, go to step 4).
3. Check Light Blue wire and Light Blue/Black wire for short to ground and repair. If wires are okay, go to step 5).
4. Replace electronic actuator.
5. Replace A/C-heater control module.
6. Check connections at A/C-heater control module connector and electronic actuator connector. Turn ignition switch to ON position. Clear A/C-heater system DTCs. See CLEARING TROUBLE CODES under TESTING. Operate A/C-heater system. If trouble code resets, go to step 5). If trouble code does not reset, recheck connections to sensor and A/C-heater control module.

CODE B0416: TEMPERATURE CONTROL NO. 1 CIRCUIT LOW (FEEDBACK CIRCUIT HIGH)

1. Turn ignition switch to ON position. Using a DVOM, backprobe A/C-heater control module connector. Check for battery voltage at A/C-heater control module connector terminals C4 and D5. If battery voltage exists on either terminal, go to next step. If battery voltage does not exist on either terminal, go to step 5).
2. Turn ignition switch to OFF position. Disconnect electronic actuator connector. Turn ignition switch to ON position. Using a DVOM, backprobe A/C-heater control module connector. Check for battery voltage at A/C-heater control module connector terminals C4 and D5. If battery voltage exists on either terminal, go to next step. If battery voltage does not exist on either terminal, go to step 9).
3. Turn ignition switch to OFF position. Disconnect A/C-heater control module connector. Turn ignition switch to ON position. Using a DVOM, backprobe A/C-heater control module connector. Check for battery voltage at A/C-heater control module connector terminals C4 and D5. If battery voltage exists on either terminal, go to next step. If battery voltage does not exists on either terminal, go to step 11).
4. Repair short to battery voltage in Light Blue wire or Light Blue/Black wire.
5. Turn ignition switch to OFF position. Disconnect electronic actuator connector. Turn ignition switch to ON position. Using a DVOM, check for voltage at electronic actuator terminals No. 9 and 10. If DVOM indicates between 4-6 volts, go to step 7). If DVOM does not indicate 4-6 volts, go to next step.
6. Check for an circuit. Repair as necessary. If circuit is okay, go to step 11).
7. Using a DVOM, check for continuity of electronic actuator connector terminal No. 7 to ground. If DVOM indicates continuity, go to next step. If DVOM does not indicate continuity, go to step 10).
8. Connect a known-good electronic actuator to connector. Reconnect A/C-heater control module. Turn ignition switch to ON position. Cycle A/C-heater control module from 85°F to 65°F and back to 85°F. Note operation of known-good actuator. If actuator operates normally, go to next step. If actuator does not move, go to step 11).
9. Replace electronic actuator.
10. Check for open Yellow wire (including A/C-heater control module). Repair as necessary. If wire is okay, go to next step.
11. Replace A/C-heater control module.