GM Service Manual Online
For 1990-2009 cars only

Functional Test

    • The operation of the air conditioning (A/C) blower at all speeds in any position except the OFF position and the engagement of the A/C compressor clutch will indicate that the electrical circuits are functioning properly.
    • The same "hand-felt" temperature of the A/C evaporator inlet pipe and the A/C receiver/dryer or the dehydrator surface of an operating system will indicate a properly charged system.
    • The operation of the A/C control head in order to distribute the air from the designed outlets will indicate proper functioning.

Performance Test

Tools Required

J 39500-B A/C Refrigerant, Recovery, Recycling and Recharging Station

  1. Park the vehicle inside or in a shaded area.
  2. Place the transmission in the PARK or the NEUTRAL position.
  3. Open the hood.
  4. Secure the hood.
  5. Remove the low pressure hose cap.
  6. Remove the high pressure hose cap.

  7. Object Number: 302193  Size: SH
  8. Connect the low pressure hose. (2)
  9. Connect the high pressure hose. (1)

  10. Start the engine.
  11. Stabilize the engine to the normal idling condition.
  12. Press the A/C button to the ON position.
  13. Press the MAX/REC/RC button to the ON position.
  14. Adjust the blower speed to the HI position.
  15. Adjust the temperature control to full cold.
  16. Carefully follow the manufacturer's instructions.

The normal temperature guideline for the pressures reading is approximately 25-30°C (77-86°F).

The normal pressure guideline at the ambient for the low pressure side is approximately 127-265 kPA (18.5-38.4 psi).

The normal pressure guideline at the ambient for the high pressure side as approximately 1373-1765 kPA (199-255.9 psi).

HFC-134a Pressure-Temperature Relationship

Pressure

Temperature

(kPa)

(psi)

(°C)

(°F)

36

5.3

-20

-4.4

67

9.7

-15

5

104

15

-10

14

147

21

-5

23

196

28

0

32

255

37

5

41

314

45

10

50

392

57

15

59

471

68

20

68

569

82

25

77

677

98

30

86

785

114

35

95

912

132

40

104

1059

154

45

113

1216

176

50

122