Component Tests and General Diagnostics

R-134a Manifold Gauge Set:

SPECIAL TOOL(S)

1. Connect the R-134a Manifold Gauge Set. Manifold Gauge Set Connection
2. Adjust the climate controls for maximum cooling.
- Start the engine.
- Select MAX A/C operation.
- Set the blower motor speed to maximum.







3. Stabilize the in-vehicle temperature at 21°C-27°C (70°F-80°F).







4. Maintain the engine speed at 1500 rpm.

NOTE: When the ambient temperatures exceed 38°C (100°F), do not run the engine above normal idle speed.







5. Determine the compressor discharge (high) pressure.
1 Record the ambient temperature.
2 Record the discharge (high) pressure.
3 The system performance is acceptable when the pressure reading falls between the upper and lower limits shown.

NOTE: In ambient temperatures between 38°C-43°C (100°F-110°F), the system performance pressures will be the same as those for ambient temperatures shown on the chart in the 32°C-38°C (90°F-100°F) range.







6. Determine the compressor suction (low) pressure.
1 Record the ambient temperature.
2 Record the suction (low) pressure.
3 The system performance is acceptable when the pressure reading falls between the upper and lower limits shown.

NOTE: In ambient temperatures between 38°C-43°C (100°F-110°F), the system performance pressures will be the same as those for ambient temperatures shown on the chart in the 32°C-38°C (90°F-100°F) range.







7. Determine the A/C clutch ON time.
1 Record the ambient temperature.
2 Record the A/C clutch ON time in seconds.
3 The system performance is acceptable when the recorded time falls between the upper and lower limits shown.

NOTE: When the ambient temperature is above 26°C (80°F), the A/C clutch may not cycle.







8. Determine the A/C clutch OFF time.
1 Record the ambient temperature.
2 Record the A/C clutch OFF time in seconds.
3 The system performance is acceptable when the recorded time falls between the upper and lower limits shown.

NOTE: When the ambient temperature is above 26°C (80°F), the A/C clutch may not cycle.







9. Determine the total A/C clutch cycle time.
1 Record the ambient temperature.
2 Record the time the A/C clutch is engaged plus the time it is disengaged (time ON plus time OFF).
3 The system performance is acceptable when the recorded time falls between the upper and lower limits shown.

NOTE: When the ambient temperature is above 26°C (80°F), the A/C clutch may not cycle.







10. Determine the A/C clutch cycle rate per minute.
1 Record the ambient temperature.
2 Record the number of A/C clutch cycles occurring in one minute.
3 The system performance is acceptable when the recorded number of cycles fall between the upper and lower limits shown.

NOTE: When the ambient temperature is above 26°C (80°F), the A/C clutch may not cycle.







11. Determine the center A/C register discharge temperature.
1 Record the ambient temperature.
2 Record the center A/C register discharge temperature.
3 The system performance is acceptable when the center A/C register discharge temperature falls between the upper and lower limits shown.

NOTE: In ambient temperatures between 38°C-43°C (100°F-110°F), the A/C register discharge temperatures will be the same as those for ambient temperatures shown on the chart in the 32°C-38°C (90°F-100°F) range.