Workshop Repair and Service Manuals GMC SIERRA
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HVAC

Heating Ventilation and Air Conditioning Control Module Scan Tool Information      Table 1: HVAC Control Module Scan Tool Data Parameters Table 2: HVAC Control Module Scan Tool Output Controls HVAC Control Module Scan Tool Data Parameters Parameter Expected Value Definition Operating...
Fastener Tightening Specifications - Cooling      Fastener Tightening Specifications Application Specification Metric English A/C High Pressure Recirculation Switch 6-Y 53-lb-in A/C Low Pressure Switch 6-Y 53-lb-in A/C Refrigerant Filter...
Heating and Air Conditioning System Description and Operation (HP2) - part 3      This feature enables the electric A/C compressor to run ata speed independent of the engine. The control system will commandthe electric A/C compressor to a speed necessary to maintain adesired cooling level rather than cycle...
Heating and Air Conditioning System Description and Operation (HP2) - part 2      The semi-cooled liquid refrigerant exits the condenserand flows through the liquid line, to the orifice tube. The orifice tube is located in the liquid line between thecondenser and the evaporator. The orifice tube is the...
Heating and Air Conditioning System Description and Operation (HP2)      Engine Coolant Engine coolant is the essential element of the heatingsystem. The thermostat controls the normal engine operating coolanttemperature. The thermostat also creates a restriction for thecooling system that promotes...
Odor Correction      Eliminating Air Conditioning Odor Odors may be emitted from the air conditioning systemprimarily at start up in hot, humid climates. The followingconditions may cause the odor: Debris is present in the HVAC module.Microbial...
Refrigerant Recovery and Recharging (Non-HP2)      Special ToolsJ 43600ACR 2000 Air Conditioning Service CenterJ 45037A/C Oil Injector For equivalent regional tools, refer toSpecial Tools. Warning:To prevent personal injury, avoid breathing A/C Refrigerantand lubricant vapor...
Refrigerant Recovery and Recharging (HP2)      Special ToolsJ 43600ACR 2000 Air Conditioning Service CenterJ 45037A/C Oil InjectorGE 48997Hybrid A/C Oil Injector Adapter Hose For equivalent regional tools, refer toSpecial Tools. Warning:To prevent personal injury, avoid...
Air Conditioning Compressor Control Module Programming and Setup Compressor      Air Conditioning Compressor Control ModuleReplacement If the Air Conditioning Compressor Control Module is replacedit must be programmed with the latest operating software andvehicle calibrations. Refer toService Programming...
Refrigerant System Specifications (Non-HP2)      Refrigerant System Specifications Application Specification Metric English PAG Oil GM P/N-12378526 for United States PAG Oil GM P/N-88900060 for Canada Accumulator Replacement 60-ml* 2-oz* * Add PAG...
Air Delivery Description and Operation - part 2      The HVAC control module sends differentsignals to the mode door actuator through the mode door controlcircuit. Zero volts drives the actuator in one direction while5-volts moves the actuator in the opposite direction.When the...
Air Delivery Description and Operation      The air delivery controls are divided into four areas: HVAC Control ComponentsAir SpeedAir DeliveryRecirculation OperationHVAC Control Components HVAC Control Module The HVAC control module is a class-2 device thatinterfaces...
Air Temperature Description and Operation - part 3      The ambient air temperature is less than 4°C (40°F).The evaporator temperature is less than 3°C (38°F).The throttle position is 100%.The A/C high side pressure is more than 2957-kPa (429-psi).The engine coolant temperature...
Air Temperature Description and Operation - part 2      Heating and A/C Operation The purpose of the heating and A/C system is to provide heated and cooled air to theinterior of the vehicle. The A/C system will also remove humidity from the interiorand reduce windshield fogging....
Air Temperature Description and Operation      The air temperature controls are divided into four areas: HVAC Control ComponentsHeating and A/C OperationEngine CoolantA/C CycleHVAC Control Components HVAC Control Module The HVAC control module is a class-2 device that...
Afterblow Enabling      The afterblow mode can be enabled using the scan tool. Theafterblow mode allows the blower motor to operate after the enginehas been turned off. This operation of the blower motor dries theevaporator core, which reduces the...
Drilling Holes into the Air Conditioning and Heater Case Module Caution      Caution:Extreme care must be taken when drilling into the air conditioning and heater casemodule. Misalignment of the hole can cause damage to the air conditioning evaporatoror temperature door requiring replacement of these...
HVAC System Control Module Programming and Setup      Each of the following service procedures may requireprogramming or setup procedures to be performed on the HVAC controlmodule or HVAC actuators. HVAC Control Module Replacement If the HVAC control module is replaced it must be...
Sensor Resistance Table      Sensor Resistance Table Temperature Ambient Air Temp Sensor or Evaporator Temp Sensor Inside Air Temp Sensor (Front or Rear) Front Upper Duct Temp Sensors Heater Duct (Lower Air Temp) Sensors, Air Temperature Sensor-...
Air Temperature Description and Operation - part 6      To place the auxiliary HVAC system in Automatic mode, the following is required: The auxiliary blower motor switch on the auxiliary HVAC control assembly must be inthe Auto position.The auxiliary mode switch on the auxiliary...
Air Temperature Description and Operation - part 5      The following conditions must be met in order for the A/C compressor clutch to turnON if they are not all met and an A/C request is made the LED on the A/C switch willflash: Ambient air temperature above 7°C (45°F)The...
Air Temperature Description and Operation - part 4      This value will not be displayedon the scan tool. The default action ensures that the HVAC system can adjust the insideair temperature near the desired temperature until the condition is fixed. The scantool parameter for the...
Air Temperature Description and Operation - part 3      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 filtersthe value of the ambient air temperature sensor for...
Air Temperature Description and Operation - part 2      As the actuator shaft rotates the changing position signal issent to the module. Once the position signal and the commanded value are the same,the module changes the control signal to 2.5-volts. Auxiliary Air Temperature...