Originally Posted by shawnvw

AUTOMATIC SYSTEM


HVAC Control Module C1

Connector Part Information

• OEM: 15491305
• Service: 15126709
• Description: 20-Way F USCAR 0.64 Series (BN)
  
  
  Terminal Part Information
• Terminal/Tray: SAITS-A03T-M064/14
• Core/Insulation Crimp: P/P
• Release Tool/Test Probe: J-38125-215/J-35616-64B (L-BU)
• 
  HVAC Control Module C1
  
  Pin
  Wire Color
  Circuit No.
  Function
  
  1
  WH/BK
  5515
  Inside Air Temperature Sensor Assembly Control
  
  2-3
  Not Used
  
  4
  D-GN
  734
  Inside Air Temperature Sensor Signal
  
  5
  GY
  1548
  Passenger Sunload Sensor Signal
  
  6
  BN
  404
  Upper Air Temperature Sensor Signal (C69)
  
  7
  L-GN
  405
  Lower Air Temperature Sensor Signal (C69)
  
  8-13
  Not Used
  
  14
  D-GN
  5518
  Auxiliary Inside Air Temperature Sensor Signal (C69)
  
  15
  L-BU/BK
  590
  Driver Sunload Sensor Signal
  
  16
  TN
  516
  Upper Left Air Temperature Sensor Signal
  
  17
  TN
  517
  Upper Right Air Temperature Sensor Signal
  
  18
  PK
  2145
  Air Temperature Switch Signal - Right (C69)
  
  19
  GY
  2599
  Auxiliary Mode Door Control (C69)
  
  20
  Not Used
  
  
  HVAC Control Module C2
  
  Connector Part Information
• OEM: 15491285
• Service: 15136073
• Description: 16-Way F Kaizen 0.64 (BK)
  
  Terminal Part Information
• Terminal/Tray: SAITS-A03T-M064/14
• Core/Insulation Crimp: P/P
• Release Tool/Test Probe: J-38125-215/J-35616-64B (L-BU)
  [ul][/ul]HVAC Control Module C2
  
  Pin
  Wire Color
  Circuit No.
  Function
  
  1
  RD/WH
  3340
  Battery Positive Voltage
  
  2-3
  Not Used
  
  4
  L-GN/BK
  735
  Ambient Air Temperature Sensor Signal
  
  5
  D-GN
  5060
  Low Speed GMLAN Serial Data
  
  6
  D-BU
  204
  A/C Low Pressure Sensor Signal
  
  7
  Not Used
  
  8
  BK/WH
  1851
  Ground
  
  9
  OG
  300
  Ignition 3 Voltage
  
  10
  WH
  193
  Rear Defog Relay Control
  
  11-14
  Not Used
  
  15
  BK
  1050
  Ground
  
  16
  D-GN
  6101
  Low Reference
  
  HVAC Control Module C3
  
  Connector Part Information
• OEM: 15491304
• Service: 15126710
• Description: 20-Way F USCAR 0.64 Series (GY)
  [ul][/ul]Terminal Part Information
• Terminal/Tray: SAITS-A03T-M064/14
• Core/Insulation Crimp: P/P
• Release Tool/Test Probe: J-38125-215/J-35616-64B (L-BU)
  [ul][/ul]HVAC Control Module C3
  
  Pin
  Wire Color
  Circuit No.
  Function
  
  1
  TN
  518
  Lower Left Air Temperature Sensor Signal
  
  2
  YE/BK
  713
  Defrost/Heater Mode Valve Position Sensor Signal
  
  3
  PU
  1838
  Recirculation Door Position Signal
  
  4
  GY/BK
  754
  Blower Motor Speed Control
  
  5-9
  Not Used
  
  10
  GY
  598
  5-Volt Reference
  
  11
  TN
  520
  Lower Right Air Temperature Sensor Signal
  
  12
  L-BU
  733
  Air Temperature Door Position Signal
  
  13
  D-BU
  1646
  Auxiliary Air Temperature Door Position Signal (C69)
  
  14
  Not Used
  
  15
  TN
  2273
  Mode Door Control
  
  16
  D-BU
  1199
  Air Temperature Door Control
  
  17
  D-GN
  1614
  Recirculation Door Control
  
  18
  WH/BK
  1236
  Auxiliary Air Temperature Door Control (C69)
  
  19
  Not Used
  
  20
  YE
  1791
  Low Reference
  
  HVAC Control Module C4 (C69)
  
  
  Connector Part Information
• OEM: 15483874
• Service: 21997401
• Description: 16-Way F Kaizen 0.64 Series (GN)
  [ul][/ul]Terminal Part Information
• Terminal/Tray: SAITS-A03T-M064/14
• Core/Insulation Crimp: P/P
• Release Tool/Test Probe: J-38125-215/J-35616-64B (L-BU)
  [ul][/ul]HVAC Control Module C4 (C69)
  
  Pin
  Wire Color
  Circuit No.
  Function
  
  1
  Not Used
  
  2
  GY
  596
  5-Volt Reference
  
  3
  OG
  2215
  Auxiliary Mode Door Control
  
  4
  GY
  2614
  Auxiliary Air Temperature Door Control
  
  5
  Not Used
  
  6
  GY/BK
  1798
  Low Reference
  
  7
  BN
  5516
  Inside Air Temperature Sensor Assembly Control
  
  8-9
  Not Used
  
  10
  D-GN
  2211
  Auxiliary Blower Motor Speed Control
  
  11-16
  Not Used

Originally Posted by shawnvw

Air Temperature Sensor

The air temperature sensors are a 2-wire negative temperature co-efficient thermistor. The vehicle uses the following air temperature sensors:
•
Ambient Air Temperature Sensor [align=left]•
Inside Air Temperature Sensor Assembly [/align][align=left]•
Upper Left Air Temperature Sensor [/align][align=left]•
Upper Right Air Temperature Sensor [/align][align=left]•
Lower Left Air Temperature Sensor [/align][align=left]•
Lower Right Air Temperature Sensor [/align][align=left]•
Upper Air Temperature Sensor - Auxiliary [/align][align=left]•
Lower Air Temperature Sensor - Auxiliary [/align]
A signal and low reference circuit enables the sensor to operate. As the air temperature surrounding the sensor increases, the sensor resistance decreases. The sensor signal voltage decreases as the resistance decreases. The sensor operates within a temperature range between -40 to +101°C (-40 to +215°F). The sensor signal varies between 0-5volts.
The input of the duct air temperature sensors are different from the ambient and inside air temperature sensors. The HVAC control module converts the signal to a range between 0-255counts. As the air temperature increases the count value will decrease. If the HVAC control module or auxiliary HVAC control module detects a malfunctioning sensor, then the control module software will use a defaulted air temperature value. The default value for the ambient and inside air temperature sensors will be displayed on the scan tool. The default value for the duct air temperature sensors will not be displayed on the scan tool. The scan tool parameter for the duct air temperature sensors are the actual state of the signal circuit. The default action ensures that the HVAC system can adjust the inside air temperature near the desired temperature until the condition is corrected.
The ambient air temperature sensor mounts underhood and can be affected by city traffic, by idling, and by restarting a hot engine. Therefore, the HVAC control module filters the value of the ambient air temperature sensor for temperature display. The ambient air temperature value is updated under the following conditions:

Condition

Display

At start up with the engine off less than 2hours
Displays last stored temperature

At start up with the engine off more than 2hours
Displays real-time temperature

Engine coolant temperature is less than 28°C (50°F) above the ambient air temperature
Displays real-time temperature

Vehicle speed above 32km/h (20mph) for a minimum of 80seconds
Displays real-time temperature

Vehicle speed above 72km/h (45mph)
Displays real-time temperature

Sensor reading is less than the last displayed value
Displays real-time temperature

The scan tool has the ability to update the displayed ambient air temperature. To update the ambient air temperature display on the HVAC control module, perform the following procedure: Turn ON the ignition. Simultaneously press the A/C and Recirc switches for 5 seconds



Sunload Sensor Assembly

The sunload sensor is a 2-wire photo diode. The vehicle uses left and right sunload sensors. The 2sensors are integrated into the sunload sensor assembly. Low reference and signal circuits enable the sensor to operate. As the light shining upon the sensor gets brighter, the sensor resistance increases. The sensor signal decreases as the resistance increases. The sensor operates within an intensity range between completely dark and bright. The sensor signal varies between 0-5volts. The HVAC control module converts the signal to a range between 0-255counts. The sunload sensor provides the HVAC control module a measurement of the amount of light shining on the vehicle. Bright, or high intensity, light causes the vehicles inside temperature to increase. The HVAC system compensates for the increased temperature by diverting additional cool air into the vehicle. If the HVAC control module detects a malfunctioning sensor, then the control module software will use a defaulted sunload value. This value will not be displayed on the scan tool. The default action ensures that the HVAC system can adjust the inside air temperature near the desired temperature until the condition is fixed. The scan tool parameter for the sunload sensor is the actual state of the signal circuit.