Test Description
The numbers below refer to the step numbers on the diagnostic table.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
Schematic Reference: HVAC Schematics DEFINITION: The A/C compressor clutch will not engage when an A/C request has been made and a Powertrain DTC has not been set. | ||||
1 | Did you perform the HVAC Diagnostic System Check? | -- | Go to Step 2 | |
Is the engine coolant temperature indicator illuminated? | -- | Go to Engine Coolant Temperature Indicator Always On in Engine Cooling | Go to Step 3 | |
3 |
Important: For A/C compressor operation, outside air temperature must be above 3°C (38°F).
Does the A/C compressor operate? | -- | Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems | Go to Step 4 |
4 |
Are the low and high side pressure values within the allowable limits for the recorded outside air temperature, and within 103 kPa (15 psi) of each other? | -- | Go to Step 5 | Go to Leak Testing in Heating, Ventilation and Air Conditioning |
5 |
Important: The A/C compressor refrigerant pressure switch allows high speed auxiliary cooling fans to turn on at approximately 1,900 kPa (276 psi). A malfunction related to this switch will allow high side A/C pressure to increase and disable the A/C clutch at approximately 2,968 kPa (430 psi). Refer to Cooling Fan Inoperative - Auxiliary in Engine Cooling. Start the engine. With a scan tool, command the A/C compressor clutch relay ON and OFF. Does the A/C compressor clutch relay turn ON and OFF with each command? | -- | Go to Step 6 | Go to Step 7 |
6 |
Does the test lamp illuminate? | -- | Go to Step 8 | Go to Step 18 |
7 |
Does the test lamp illuminate? | -- | Go to Step 10 | Go to Step 17 |
8 |
Does the A/C compressor clutch engage? | -- | Go to Step 19 | Go to Step 9 |
9 | Test the A/C compressor clutch supply voltage circuit at the A/C compressor clutch for a short to ground, a high resistance, or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 27 | Go to Step 14 |
10 |
Does the test lamp turn ON and OFF with each command? | -- | Go to Step 19 | Go to Step 11 |
11 | Does the test lamp remain illuminated with each command? | -- | Go to Step 12 | Go to Step 13 |
12 | Test the control circuit and A/C cut out input circuit of the A/C compressor clutch relay for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 27 | Go to Step 20 |
13 | Test the control circuit of the A/C compressor clutch relay for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 27 | Go to Step 20 |
14 | Test the ground circuit from the A/C compressor clutch to the secondary cooling fan temperature switch for a high resistance or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 27 | Go to Step 15 |
15 | Test the ground circuit of the secondary cooling fan temperature switch for a high resistance or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 27 | Go to Step 16 |
16 |
Important: Before performing this step, engine coolant temperature must be less than 120°C (248°F). Measure the resistance between the switch side, secondary cooling fan temperature switch terminals. Does the resistance measure near the specified value? | 0.0ohms | Go to Step 21 | Go to Step 22 |
17 | Repair the coil side voltage supply circuit of the A/C compressor clutch relay. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 27 | -- |
18 | Repair the switch side voltage supply circuit of the A/C compressor clutch relay. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 27 | -- |
19 | Inspect for poor connections at the A/C compressor clutch relay. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 27 | Go to Step 23 |
20 | Inspect for poor connections at the harness connector of the Engine Control Module (ECM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 27 | Go to Step 26 |
21 | Inspect for poor connections at the harness connector of the A/C compressor clutch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 27 | Go to Step 25 |
22 | Inspect for poor connections at the harness connector of the secondary cooling fan temperature switch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 27 | Go to Step 24 |
23 | Replace the A/C compressor clutch relay. Did you complete the replacement? | -- | Go to Step 27 | -- |
24 | Replace the secondary cooling fan temperature switch. Refer to Engine Cooling Fan Control Switch Replacement in Engine Cooling Systems. Did you complete the replacement? | -- | Go to Step 27 | -- |
25 | Replace the A/C compressor clutch. Refer to Air Conditioning Clutch Coil Removal and Air Conditioning Clutch Coil Installation in Heating, Ventilation, and Air Conditioning. Did you complete the replacement? | -- | Go to Step 27 | -- |
26 |
Important: Perform the reprogramming procedure for the PCM. Replace the Engine Control Module (ECM). Refer to Engine Control Module Replacement in Engine Controls-3.0L. Did you complete the replacement? | -- | Go to Step 27 | -- |
27 | Operate the system in order to verify the repair. Did you correct the condition? | -- | System OK | Go to Step 4 |
