LEMON Manuals: Even more car manuals for everyone
Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> Heating, Ventilation & A/C (HVAC) >> HVAC Control Systems >> HVAC Systems - Manual >> System Tests >> A/C Pressure Zone "B" Diagnosis

A/C Pressure Zone "B" Diagnosis

WARNING: Avoid contact with moving parts and hot surfaces while working around a running engine in order to prevent physical injury.
NOTE: Definition: The low side pressure is greater than normal and the high side pressure is lower than normal.
  1. Were you sent here from the A/C PERFORMANCE TEST? If so, go to next step. If not, see A/C PERFORMANCE TEST  under PERFORMANCE TESTS.
  2. After continued operation of the A/C system, do the low and high side pressures equalize or become static? If so, go to step  5. If not, go to next step.
  3. Refer to the pressures recorded during the A/C SYSTEM PERFORMANCE TEST. See A/C PERFORMANCE TEST  under PERFORMANCE TESTS. Inspect for the following conditions:
    • The low side pressure equal to or above the specified pressure range of the A/C PERFORMANCE TEST TABLE. See Figure.
    • The high side pressure is below the specified pressure range of the A/C PERFORMANCE TEST TABLE.
    • The low side refrigerant line at the compressor feels cool-to-warm.
    • The high side refrigerant line at the compressor feels warm-to-hot.
    Do the listed conditions exist? If so, go to step  5. If not, go to next step.
  4. Refer to the pressures recorded during the A/C System Performance Test. See A/C PERFORMANCE TEST  under PERFORMANCE TESTS. Inspect for the following conditions:
    • The low side pressure is above the specified pressure range of the A/C Performance Table. See Figure.
    • The high side pressure is below the specified pressure range of the A/C Performance Table.
    • The low side refrigerant line at the compressor feels warm.
    • The high side refrigerant line at the compressor feels warm to hot.
    Do the listed conditions exist? If so, go to next step. If not, see A/C PERFORMANCE TEST  under PERFORMANCE TESTS.
  5. The A/C system has a low refrigerant charge. Evacuate and recharge the A/C system. See RECOVERY, EVACUATING & RECHARGING in GENERAL SERVICING PROCEDURES article in GENERAL SERVICING. After repairs are completed, go to next step.
  6. After you perform the repairs, record the low and the high side pressures and I/P panel outlet air temperature. Compare the pressures and the temperature to those listed in the A/C System Performance Chart. See Figure. Are the readings within the specified ranges? If so, go to step  13. If not, go to next step.
  7. The A/C compressor is malfunctioning. Remove the orifice tube and inspect for contamination. See ORIFICE TUBE  under REMOVAL & INSTALLATION. Are there metal flakes on the orifice tube? If so, go to step  9. If not, go to next step.
  8. Inspect the orifice tube for a Brown, powdery residue indicating desiccant in the A/C system. Is there a Brown, powdery residue present? If so, go to step  11. If not, go to step  12.
  9. Remove the compressor hose from the compressor. See COMPRESSOR HOSE ASSEMBLY  under REMOVAL & INSTALLATION. Inspect for metal flake contamination at the line connections and the compressor ports. Is there metal flake contamination present? If so, go to step  12. If not, go to step  12.
  10. Replace the A/C compressor. See COMPRESSOR  under REMOVAL & INSTALLATION. Install an A/C refrigerant filter. See REFRIGERANT FILTER  under REMOVAL & INSTALLATION. Replace the orifice tube. See ORIFICE TUBE  under REMOVAL & INSTALLATION. Evacuate and recharge the A/C system. See RECOVERY, EVACUATING & RECHARGING in GENERAL SERVICING PROCEDURES article in GENERAL SERVICING. After repairs are complete, go to step  13.
  11. Flush the A/C system. See FLUSHING PROCEDURES in GENERAL SERVICING PROCEDURES article in GENERAL SERVICING. Replace the orifice tube. See ORIFICE TUBE  under REMOVAL & INSTALLATION. Replace the A/C compressor. See COMPRESSOR  under REMOVAL & INSTALLATION. Replace the accumulator. See ACCUMULATOR  under REMOVAL & INSTALLATION. Evacuate and recharge the A/C system. See RECOVERY, EVACUATING & RECHARGING in GENERAL SERVICING PROCEDURES article in GENERAL SERVICING. After repairs are complete, go to step  13.
  12. Replace the A/C compressor. See COMPRESSOR  under REMOVAL & INSTALLATION. Evacuate and recharge the A/C system. See RECOVERY, EVACUATING & RECHARGING in GENERAL SERVICING PROCEDURES article in GENERAL SERVICING. After repairs are complete, go to step  13.
  13. Operate the system in order to verify the repair. Did you find and correct the condition? If so, system is okay. If not, go to SYMPTOM DIAGNOSIS  under TROUBLE SHOOTING.
scientia non olet · About LEMON Manuals