Auto. A/C Systems - Troubleshooting & Diagnosis

• Isolating The Problem
  • Notes
  • Functional Performance Test
    • "DEF - Dial @ 85
    • "BI-LEVEL" - Dial @ 75
    • "HP - Dial @ 65
    • "AUTO" - Dial @ 65
    • "AUTO" - Dial @ 85
    • "LO" - Dial @ 85
    • "ECONOMY" - Dial @ 65
    • "OFF" - Dial @ 65
• Temperature Control Problem
  • System Operates Only At Max A/C
  • System Operates Only At Max Heat
  • System Fluctuates Blower Speeds And/Or Mode Shifts During Acceleration
  • Dial Setting Does Not Provide Comfort
  • Blower Cycling & Mode Cycling
  • Insufficient Cooling Or Heating
• Blower Control Circuit Problem
  • System Operates Only At Low Blower
  • No Blower Operation In Any Lever Setting
  • No Blower In "Off" Or "Lo" Setting
  • Blower Speed Varies In "Hi" Or "Def"
  • Blower Operates With Ignition Off
  • Blower Speeds Skipped In "Auto", "BILEVEL" & "Economy" Settings
  • No Heater Turn On In Cold Weather Except In "Def"
  • Immediate Heater Turn On In Cold Weather
  • A/C Delayed In Hot Weather Until Engine Warms Up
  • BLOWER OPERATION ONLY IN "Hi" OR "DEF"
• Auxiliary Vacuum Problem
  • Notes
  • A/C Mode Door Actuation Problem
  • Defroster Bleed Problems
    • Notes
    • No Defroster Bleed
    • Rapid Fogging of Windshield When Heater Turns On
  • Defroster Door Actuation Problems
  • Recirculating Air Door Actuation Problems
  • Auxiliary Vacuum Circuit Test
• Refrigeration Problem
  • Inefficient Cooling