GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 1998 🢒 DeVille 🢒 HVAC 🢒 HVAC Systems - Automatic 🢒 Cooling Insufficient - Air Conditioning (A/C) Inoperative

Step

Action

Value(s)

Yes

No

1

Are any HVAC DTCs or PCM DTCs stored?

--

For HVAC DTCs, refer to Self-Diagnostics

For PCM DTCs, refer to Diagnostic Trouble Code (DTC) List/Type

Go to Step 2

2
  1. Inspect the outer surface of the condenser for items that may restrict the air flow. Remove the follwoing items as necessary:
    2. • Dirt
    • Leaves
    • Any other material
  2. Inspect the area between the condenser and the radiator for items that may restrict air flow. Remove the following items as necessary:
    3. • Dirt
    • Leaves
    • Any other material
  3. Inspect the condenser and the refrigerant lines or hoses for the following conditions. Replace any damaged components. Follow the instructions found later in this section:
    4. • Dents
    • Kinks
    • Other restrictions
  4. Inspect the following parts for evidence of refrigerant leaks. Repair or replace any damaged components. Follow the instructions found later in this section:
    5. • The condenser
    • The refrigerant lines or hoses
    • All component connections
  5. With the A/C compressor operating, compare the clutch hub speed to the pulley speed. If clutch slippage is indicated, replace the clutch. Refer to Compressor Clutch Plate and Hub Assembly Removal (HT6/HD6)
  6. Select the A/C mode.
  7. With the engine idling and the A/C compressor operating, inspect the engine cooling fan operation.

Is the left cooling fan operating at low speed and is the right cooling fan operating at high speed?

--

Go to Step 3

Go to Operating Modes

3
  1. Verify that the ambient temperature is not less than the specified value.
  2. Idle the engine at normal operating temperature.
  3. Open the hood and all of the body doors.
  4. Set the temperature control to the MAX COLD position.
  5. Set the blower control to the HIGH position.
  6. Feel the condenser outlet in front of the expansion (orifice) tube.

Does the condenser outlet feel warm?

21°C (70°F)

Go to Step 5

Go to Step 4

4

A restriction exists in the high side of the system.

  1. Inspect for frost in order to locate the restriction.
  2. Recover the refrigerant. Refer to Refrigerant Recovery and Recharging .
  3. Repair as required.
  4. Recharge the A/C system. Refer to Refrigerant Recovery and Recharging .

Did you complete the repair?

--

System OK

--

5
    • Feel the evaporator inlet pipe.
    • Feel the accumulator surface.

Does the evaporator inlet pipe feel noticeably colder than the accumulator surface?

--

Go to Step 6

Go to Step 8

6

A low refrigerant charge is indicated.

Perform a leak test of the A/C system. Refer to Leak Testing .

Did you find and correct a leak?

--

Go to Step 7

Go to Step 8

7
  1. Recover the refrigerant. Refer to Refrigerant Recovery and Recharging .
  2. Repair as needed.
  3. Recharge the A/C system. Refer to Refrigerant Recovery and Recharging .

Did you complete the repair?

--

System OK

--

8
  1. Install the J 39500-B in order to monitor the A/C system high-side and low-side pressures.
  2. Observe the low-side pressure gage.

Do the following actions occur?

    • The compressor turns OFF when the pressure drops to nearly the minimum specified value.
    • The compressor turn ON again when the pressure rises to nearly the maximum specified value.

Minimum: 69 kPa (10 psi)

Maximum: 138 kPa (20 psi)

Go to Step 14

Go to Step 9

9

Inspect the compressor.

Does the compressor run continuously?

--

Go to Step 11

Go to Step 10

10

The compressor cycles low or high.

Replace the faulty pressure recycling switch. Refer to Air Conditioning (A/C) High Pressure Cut-Out Switch Replacement .

Did you complete the repair?

--

System OK

--

11
  1. Disconnect the blower motor connector.
  2. Observe the following components:
    3. • The low-side pressure gage
    • The A/C compressor clutch

Does the A/C compressor run continuously while the low-side pressure drops below the specified value?

69 kPa (10 psi)

Go to Step 12

Go to Step 13

12

Replace the faulty pressure recycling switch. Refer to Air Conditioning (A/C) High Pressure Cut-Out Switch Replacement .

Did you complete the repair?

--

Go to Step 14

--

13
  1. One of the following conditions exists:
    2. • The compressor shuts off when the pressure drops to the maximum specified value.
    • The pressure never drops to the minimum specified value, and the A/C compressor runs continuously.
  2. Reconnect the blower motor.

Is the blower motor reconnected?

Minimum: 69 kPa (10 psi)

Maximum: 138 kPa (20 psi)

Go to Step 14

--

14
  1. Record the ambient temperature and the relative humidity.
  2. Select the AUTO mode.
  3. Set the temperature control to the MAX COLD position.
  4. Set the blower control to the HIGH position.
  5. Close all of the windows and the doors of the vehicle.
  6. Run the engine at idle.
  7. Install a thermometer in the vehicle A/C outlet. Wait for 10 minutes.
  8. Verify the system performance. Refer to System Performance Test .

Is the A/C outlet temperature within chart limits?

--

Go to Step 15

Go to Step 16

15

The refrigeration system is operating properly.

Verify that the control portion of the A/C system is operating properly. Refer to Functional Check .

Did you perform the functional test?

--

System OK

--

16

Observe the compressor operation during the performance test.

Does the compressor cycle?

--

Go to Step 17

Go to Step 18

17
  1. Recover the refrigerant. Refer to Refrigerant Recovery and Recharging .
  2. Verify that the expansion (orifice) tube is not plugged. Refer to Expansion (Orifice) Tube Replacement .
  3. Recharge the A/C system. Refer to Refrigerant Recovery and Recharging .

Did you complete the repair?

--

System OK

--

18

The compressor runs continuously.

  1. Recover the refrigerant. Refer to Refrigerant Recovery and Recharging .
  2. Inspect the expansion tube. Refer to Expansion (Orifice) Tube Replacement .

Is the expansion (orifice) tube missing?

--

Go to Step 19

Go to Step 20

19
  1. Install a new expansion tube. Refer to Expansion (Orifice) Tube Replacement .
  2. Recharge the A/C system. Refer to Refrigerant Recovery and Recharging .

Did you complete the repair?

--

System OK

--

20

Examine the suction line between the compressor and the pressure cycling switch. Refer to Compressor Hose Assembly Replacement .

Did you find a restriction?

--

Go to Step 21

Go to Step 22

21
  1. Repair as needed.
  2. Recharge the A/C system. Refer to Refrigerant Recovery and Recharging .

Did you complete the repair?

--

System OK

--

22

A system overcharge is indicated. Recharge the A/C system. Refer to Refrigerant Recovery and Recharging .

Did you complete the repair?

--

System OK

--