Step
| Action
| Value(s)
| Yes
| No
|
1
| Are
any HVAC DTCs or PCM DTCs stored?
| --
| For HVAC DTCs, Go to
Self-Diagnostics
For PCM DTCs, Go to
Diagnostic Trouble Code (DTC) List/Type
in Body Control System
| Go to
Step 2
|
2
|
- Inspect the outer surface of the condenser for the following items
that may restrict the air flow. Remove as necessary.
- Inspect the area between the condenser and the radiator for the
following items that may restrict air flow. Remove as necessary.
- Inspect the condenser and the refrigerant lines or hoses for the
following conditions. Replace damaged components by following the instructions
found later in this section.
- Inspect the following parts for evidence of refrigerant leaks.
Repair or replace damaged components following instructions found later in
this section.
• | The refrigerant lines or hoses |
• | All component connections |
- 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)
- Select the A/C mode.
- 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
|
- Verify that the ambient temperature is not less than the specified
value.
- Idle the engine at normal operating temperature.
- Open the hood and all of the body do
- Set the temperature control to the MAX COLD position.
- Set the blower control to the HIGH position.
- 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.
- Inspect for frost in order to locate the restriction.
- Recover the refrigerant. Refer to
Refrigerant Recovery and Recharging
- Repair as required.
- 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
|
- Recover the refrigerant. Refer to
Refrigerant Recovery and Recharging
- Repair as required.
- Recharge the A/C system. Refer to
Refrigerant Recovery and Recharging
Is the repair complete?
| --
| System OK
| --
|
8
|
- Install theJ 39500-B
ACR4 in order to monitor the A/C system high-side and low-side pressures.
- 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 switch. Refer to
Temperature Sensor Replacement - Low Side
.
Is the repair complete?
| --
| System OK
| --
|
11
|
- Disconnect the blower motor connector.
- Observe the following components:
• | 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 switch. Refer to
Temperature Sensor Replacement - Low Side
.
Is the repair complete?
| --
| Go to
Step 14
| --
|
13
| One of the following conditions exists:
• | 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. |
Reconnect the blower motor.
Is the blower motor reconnected?
| Minimum: 69 kPa (10 psi)
Maximum: 138 kPa (20 psi)
| Go to
Step 14
| --
|
14
|
- Record the ambient temperature and the relative humidity.
- Select the AUTO mode.
- Set the temperature control to the MAX COLD position.
- Set the blower control to the HIGH position.
- Close all of the windows and the doors of the vehicle.
- Run the engine at idle.
- Install a thermometer in the vehicle A/C outlet. Wait for 10 minutes.
- 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
|
- Recover the refrigerant. Refer to
Refrigerant Recovery and Recharging
- Verify that the expansion (orifice) tube is not plugged. Refer
to
Expansion (Orifice) Tube Replacement
- Recharge the A/C system. Refer to
Refrigerant Recovery and Recharging
Is the repair complete?
| --
| System OK
| --
|
18
| The compressor runs continuously.
Recover the refrigerant. Refer to
Refrigerant Recovery and Recharging
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
|
- Install a new expansion tube. Refer to
Expansion (Orifice) Tube Replacement
- Recharge the A/C system. Refer to
Refrigerant Recovery and Recharging
Is the repair complete?
| --
| 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
|
- Repair as required
- Recharge the A/C system. Refer to
Refrigerant Recovery and Recharging
Is the repair complete?
| --
| System OK
| --
|
22
| A system overcharge is indicated. Recharge the A/C system.
Refer to
Refrigerant Recovery and Recharging
Is the repair complete?
| --
| System OK
| --
|