Heating and Air Conditioning: Technical Service Bulletins

• Customer Interest
  • Body - Broken Rear Window Defogger Grid Detection
  • A/C - Musty Odors Emitted From (HVAC) System
  • Vehicle - Electrical Problems, IPC Codes 33, 34, 37, 39
  • A/C - Whistle Noise When Coming Off Full Hot Setting
  • Heater Duct - Condensation Dripping
  • A/C Compressor - Moan Noise
  • A/C - Overheat, A/C Compressor OFF (Intermittent)
  • Heater - Poor Heat Distribution
  • Heater - Insufficient Heat Distribution, Low Air Flow
  • A/C - Odor at Start up in Humid Climates
  • A/C System - Odor Primarily Upon Start Up
    • Overview
    • Procedure A (Replace Evaporator Core)
    • Procedure B (Clean and Disinfect)
    • Procedure C (Install Afterblow Module)
    • Procedure D (Enabling Afterblow Mode)
  • A/C - Odor With Start Up In Humid Climates
    • Overview
    • Afterblow Module Wiring Diagrams
      • 1985 to 1993 DeVille/FWD Fleetwood/Sixty Special
      • 1986 to 1991 Eldorado/Seville
      • 1992 & 1993 Eldorado/Seville
      • 1987 to 1993 Allante
• By Symptom
  • Abnormal wear/deterioration
    • A/C - R-134a System Flushing Procedures
  • Customer Interest
    • Body - Broken Rear Window Defogger Grid Detection
    • A/C - Musty Odors Emitted From (HVAC) System
    • Vehicle - Electrical Problems, IPC Codes 33, 34, 37, 39
    • A/C - Whistle Noise When Coming Off Full Hot Setting
    • Heater Duct - Condensation Dripping
    • A/C Compressor - Moan Noise
    • A/C - Overheat, A/C Compressor OFF (Intermittent)
    • Heater - Poor Heat Distribution
    • Heater - Insufficient Heat Distribution, Low Air Flow
    • A/C - Odor at Start up in Humid Climates
    • A/C System - Odor Primarily Upon Start Up
      • Overview
      • Procedure A (Replace Evaporator Core)
      • Procedure B (Clean and Disinfect)
      • Procedure C (Install Afterblow Module)
      • Procedure D (Enabling Afterblow Mode)
    • A/C - Odor With Start Up In Humid Climates
      • Overview
      • Afterblow Module Wiring Diagrams
        • 1985 to 1993 DeVille/FWD Fleetwood/Sixty Special
        • 1986 to 1991 Eldorado/Seville
        • 1992 & 1993 Eldorado/Seville
        • 1987 to 1993 Allante
  • Erratic Operation
    • Vehicle - Electrical Problems, IPC Codes 33, 34, 37, 39
  • Inoperative
    • A/C - Overheat, A/C Compressor OFF (Intermittent)
  • Leaks
    • Heater Duct - Condensation Dripping
    • A/C - Leak Test
      • Overview
      • General Description
      • Leak Testing the Refrigeration System
        • Overview
        • Electric Halogen Leak Detector
        • Fluorescent Leak Detector
        • Liquid Leak Detectors and Pressure Testing
    • A/C - R134a Leak Detection With Tracer Dye
  • Noise
    • A/C - Whistle Noise When Coming Off Full Hot Setting
    • A/C Compressor - Moan Noise
    • A/C Compressor - Moan Noises Under Light Acceleration
  • Odors
    • A/C - Musty Odors Emitted From (HVAC) System
    • A/C - Odor at Start up in Humid Climates
    • A/C - Odors on Hot/Humid Start Up
      • Overview
      • Procedure A (Replace Evaporator Core)
      • Procedure B (Clean and Disinfect)
      • Procedure C (Install Afterblow Module, P/N 25533406)
    • A/C System - Odor Primarily Upon Start Up
      • Overview
      • Procedure A (Replace Evaporator Core)
      • Procedure B (Clean and Disinfect)
      • Procedure C (Install Afterblow Module)
      • Procedure D (Enabling Afterblow Mode)
    • A/C - Odor With Start Up In Humid Climates
      • Overview
      • Afterblow Module Wiring Diagrams
        • 1985 to 1993 DeVille/FWD Fleetwood/Sixty Special
        • 1986 to 1991 Eldorado/Seville
        • 1992 & 1993 Eldorado/Seville
        • 1987 to 1993 Allante
  • Overheating
    • A/C - Overheat, A/C Compressor OFF (Intermittent)
  • Poor performance
    • Heater - Poor Heat Distribution
    • Heater - Insufficient Heat Distribution, Low Air Flow
  • Starting problems
    • Vehicle - Electrical Problems, IPC Codes 33, 34, 37, 39
  • Won't turn off
    • Vehicle - Electrical Problems, IPC Codes 33, 34, 37, 39
• All Technical Service Bulletins
  • Vehicle - Engine And Sub Systems Flushing Info. (CANADA)
  • Vehicle - Engine And Sub-Systems Flushing Recommendations
  • Body - Broken Rear Window Defogger Grid Detection
  • A/C - Musty Odors Emitted From (HVAC) System
  • A/C - R-134a System Flushing Procedures
  • Vehicle - Electrical Problems, IPC Codes 33, 34, 37, 39
  • A/C - PureGuard 2 Operating Alert
    • Overview
    • Refrigerant Recovery
    • Oil Injection and Refrigerant Charging
    • Additional ACR4 Operation and Maintenance Tips
    • Tank-to-Tank Refrigerant Transfer
    • Excess Air In Tank
    • Pureguard 2 Error Codes
    • Active Flow Control
  • A/C - Tool And Equipment Maintenance
  • A/C - Retrofitting R-12 to R-134a
    • Overview
    • A. Retrofit Procedure
      • Notes on Retrofit
      • Compressors
      • Accumulator /Dryer
      • High Pressure Cut-Off Switch (HPCOS)
      • Platform Details
      • Compressor Replacement Chart
      • Compressor Availability
      • Geo Models
      • 1985-88 Nova, 1989-93 Prizm (S)
      • 1985-88 Sprint, 1989-93 Metro (M)
      • 1989-93 Tracker
      • 1985-89 Spectrum and 1990-93 Storm (R)
    • B. General Information
    • C. Parts Information
    • D. Warranty Information
  • A/C - Systems With R12 Or R134a Service Issue
    • Overview
    • R12 System Retrofitting to R134A
    • Servicing R134A Retrofitted Vehicle Systems
    • R12 and R134A Refrigerants Are Not Interchangeable
    • J 41810 Pureguard 2 R134A Refrigerant Monitor
    • Summarizing GM's A/C Service Recommendations
  • A/C - Whistle Noise When Coming Off Full Hot Setting
  • Tools - A/C Leak Detector Maintenance Kit Availability
    • Overview
    • Service Procedure
  • A/C Refrigerant - Contamination
  • Heater Duct - Condensation Dripping
  • A/C - Leak Test
    • Overview
    • General Description
    • Leak Testing the Refrigeration System
      • Overview
      • Electric Halogen Leak Detector
      • Fluorescent Leak Detector
      • Liquid Leak Detectors and Pressure Testing
  • A/C Compressor - Moan Noise
  • A/C Compressor - Revised Service or Unit Repair
  • A/C - Overheat, A/C Compressor OFF (Intermittent)
  • A/C - Refrigerant (R-134A) Information
  • A/C - Compressor Overhaul Service Manual Update
  • A/C Compressor - Moan Noises Under Light Acceleration
  • A/C Compressor Seal Washer - Reference Chart
  • A/C - Unnecessary Compressor Replacement
  • Heater - Poor Heat Distribution
  • Heater - Insufficient Heat Distribution, Low Air Flow
  • A/C - Odor at Start up in Humid Climates
  • A/C - Odors on Hot/Humid Start Up
    • Overview
    • Procedure A (Replace Evaporator Core)
    • Procedure B (Clean and Disinfect)
    • Procedure C (Install Afterblow Module, P/N 25533406)
  • A/C System - Odor Primarily Upon Start Up
    • Overview
    • Procedure A (Replace Evaporator Core)
    • Procedure B (Clean and Disinfect)
    • Procedure C (Install Afterblow Module)
    • Procedure D (Enabling Afterblow Mode)
  • A/C - Odor With Start Up In Humid Climates
    • Overview
    • Afterblow Module Wiring Diagrams
      • 1985 to 1993 DeVille/FWD Fleetwood/Sixty Special
      • 1986 to 1991 Eldorado/Seville
      • 1992 & 1993 Eldorado/Seville
      • 1987 to 1993 Allante
  • A/C - R134a Leak Detection With Tracer Dye
  • Contaminated R12 Refrigerant - Testing & Handling
  • A/C - R12 or R134a Service Recommendations
    • Overview
    • R12 Service Recommendations
    • R134A Service Recommendations
  • A/C - Retrofitting R-12 Vehicles to R-134A
  • A/C - Refrigerant Recovery/Recharge Equipment
  • A/C - Contaminated R134A Refrigerant
  • Cooling System, A/C - Aluminum Heater Cores/Radiators