HVAC Compressor Clutch Does Not Engage 6.5L
Test Description
The numbers below refer to the step numbers on the diagnostic table.
Step | Action | Value | Yes | No |
|---|---|---|---|---|
Schematic Reference: HVAC Schematics DEFINITION: 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 review the HVAC operation and perform the necessary inspections? | -- | Go to Step 2 | |
Does the scan tool indicate that the ECT parameter is below 124°C (256°F)? | -- | Go to Step 3 | Go to Engine Overheating | |
3 |
Important: Ambient 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 pressure values within the specifications for the ambient 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 |
Is the HVAC control assembly inoperative? | -- | Go to Step 7 | Go to Step 6 | |
6 |
Does the scan tool indicate that the A/C Request parameter is YES? | -- | Go to Step 13 | Go to Step 9 |
7 | Test the voltage supply circuits to the HVAC control assembly 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 37 | Go to Step 8 |
8 | Test the ground circuit to the HVAC control assembly for an 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 37 | Go to Step 28 |
9 |
Does the scan tool indicate that the A/C Request parameter is YES? | -- | Go to Step 29 | Go to Step 10 |
10 |
Does the scan tool indicate that the A/C Request parameter is YES? | -- | Go to Step 26 | Go to Step 11 |
11 |
Did you find and correct the condition? | -- | Go to Step 37 | Go to Step 12 |
12 | Measure the voltage from the A/C Request signal circuit at the powertrain control module (PCM). Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Does the voltage measure near the specified value? | B+ | Go to Step 30 | Go to Step 28 |
13 | 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 14 | Go to Step 16 |
14 |
Does the test lamp illuminate? | -- | Go to Step 15 | Go to Step 24 |
15 |
Does the A/C compressor clutch engage? | -- | Go to Step 25 | Go to Step 19 |
16 |
Does the test lamp illuminate? | -- | Go to Step 17 | Go to Step 23 |
17 |
Does the test lamp turn ON and OFF with each command? | -- | Go to Step 25 | Go to Step 18 |
18 | Does the test lamp remain illuminated with each command? | -- | Go to Step 21 | Go to Step 22 |
19 | 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 37 | Go to Step 20 |
20 | Test the ground circuit of the A/C compressor clutch 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 37 | Go to Step 27 |
21 | Test the control 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 37 | Go to Step 30 |
22 | 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 37 | Go to Step 30 |
23 | 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 37 | -- |
24 | 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 37 | -- |
25 | 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 37 | Go to Step 31 |
26 | Inspect for poor connections at the harness connector of the A/C low pressure 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 37 | Go to Step 32 |
27 | 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 37 | Go to Step 34 |
28 | Inspect for poor connections at the harness connector of the HVAC control assembly. 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 37 | Go to Step 35 |
29 | Inspect for poor connections at the harness connector of the A/C high pressure 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 37 | Go to Step 33 |
30 | Inspect for poor connections at the harness connector of the PCM. 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 37 | Go to Step 36 |
31 | Replace the A/C compressor clutch relay. Refer to Compressor Relay Replacement in Heating, Ventilation and Air Conditioning. Did you complete the replacement? | -- | Go to Step 37 | -- |
32 | Replace the A/C low pressure switch. Refer to Air Conditioning (A/C) Low Pressure Switch Replacement in Heating, Ventilation and Air Conditioning. Did you complete the replacement? | -- | Go to Step 37 | -- |
33 | Replace the A/C high pressure switch. Refer to Air Conditioning (A/C) High Pressure Switch Replacement in Heating, Ventilation and Air Conditioning. Did you complete the replacement? | -- | Go to Step 37 | -- |
34 | Replace the A/C compressor clutch coil. Refer to Air Conditioning Clutch Coil Replacement in Heating, Ventilation and Air Conditioning. Did you complete the replacement? | -- | Go to Step 37 | -- |
35 | Replace the HVAC control assembly. Refer to Heater and Air Conditioning Control Replacement . Did you complete the replacement? | -- | Go to Step 37 | -- |
36 |
Important: Perform the programming procedure for the PCM. Replace the PCM. Refer to Powertrain Control Module Replacement in Engine Controls - 6.5L. Did you complete the replacement? | -- | Go to Step 37 | -- |
37 | Operate the system in order to verify the repair. Did you correct the condition? | -- | System OK | Go to Step 4 |
HVAC Compressor Clutch Does Not Engage Except 6.5L
Test Description
The numbers below refer to the step numbers on the diagnostic table.
Step | Action | Value | Yes | No | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
Schematic Reference: HVAC Schematics DEFINITION: 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 review the HVAC operation and perform the necessary inspections? | -- | Go to Step 2 | |||||||
Does the scan tool indicate that the ECT parameter is below 121°C (250°F)? | -- | Go to Step 3 | Go to Engine Overheating | |||||||
3 |
Important: Ambient 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 pressure values within the specifications for the ambient 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 | ||||||
Is the HVAC control assembly inoperative? | -- | Go to Step 7 | Go to Step 6 | |||||||
6 |
Does the scan tool indicate that the A/C Request parameter is YES? | -- | Go to Step 9 | Go to Step 10 | ||||||
7 | Test the voltage supply circuits to the HVAC control assembly 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 41 | Go to Step 8 | ||||||
8 | Test the ground circuit to the HVAC control assembly for an 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 41 | Go to Step 32 | ||||||
9 | Does the scan tool indicate the A/C Compressor Cycling Switch parameter is normal? | -- | Go to Step 16 | Go to Step 11 | ||||||
10 |
Does the scan tool indicate that the A/C Request parameter is YES? | -- | Go to Step 33 | Go to Step 12 | ||||||
11 |
Does the scan tool indicate the A/C Compressor Cycling Switch parameter is normal? | -- | Go to Step 30 | Go to Step 14 | ||||||
12 |
Did you find and correct the condition? | -- | Go to Step 41 | Go to Step 13 | ||||||
13 | Measure the voltage from the A/C request signal circuit at the powertrain control module (PCM). Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Does the voltage measure near the specified value? | B+ | Go to Step 34 | Go to Step 32 | ||||||
14 | Test the A/C low pressure switch signal circuit 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 41 | Go to Step 15 | ||||||
15 | Test the ground circuit of the A/C low pressure 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 41 | Go to Step 34 | ||||||
16 | 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 17 | Go to Step 19 | ||||||
17 |
Does the test lamp illuminate? | -- | Go to Step 18 | Go to Step 27 | ||||||
18 | Connect a 10-amp fused jumper wire between the switch side voltage circuit of the A/C compressor clutch relay and the A/C compressor clutch supply voltage circuit of the A/C compressor clutch. Does the A/C compressor clutch engage? | -- | Go to Step 29 | Go to Step 22 | ||||||
19 |
Does the test lamp illuminate? | -- | Go to Step 20 | Go to Step 26 | ||||||
20 |
Does the test lamp turn ON and OFF with each command? | -- | Go to Step 29 | Go to Step 21 | ||||||
21 | Does the test lamp remain illuminated with each command? | -- | Go to Step 24 | Go to Step 25 | ||||||
22 | Test the A/C compressor clutch supply voltage circuit 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 41 | Go to Step 23 | ||||||
23 | Test the ground circuit of the A/C compressor clutch 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 41 | Go to Step 31 | ||||||
24 | Test the control 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 41 | Go to Step 34 | ||||||
25 | Test the control circuit of the A/C compressor clutch relay for an open or a short to power. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 41 | Go to Step 34 | ||||||
26 | Repair the coil side voltage supply circuit of the A/C compressor clutch relay for an open or short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 41 | -- | ||||||
27 | Test 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 41 | -- | ||||||
28 | Repair the compressor clutch supply voltage circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. | -- | Go to Step 41 | -- | ||||||
29 | 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 41 | Go to Step 35 | ||||||
30 | Inspect for poor connections at the harness connector of the A/C low pressure 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 41 | Go to Step 36 | ||||||
31 | 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 41 | Go to Step 38 | ||||||
32 | Inspect for poor connections at the harness connector of the HVAC control assembly. 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 41 | Go to Step 39 | ||||||
33 | Inspect for poor connections at the harness connector of the A/C high pressure 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 41 | Go to Step 37 | ||||||
34 | Inspect for poor connections at the harness connector of the PCM. 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 41 | Go to Step 40 | ||||||
35 | Replace the A/C compressor clutch relay. Refer to Compressor Relay Replacement in Heating, Ventilation and Air Conditioning. Did you complete the replacement? | -- | Go to Step 41 | -- | ||||||
36 | Replace the A/C low pressure switch. Refer to Air Conditioning (A/C) Low Pressure Switch Replacement in Heating, Ventilation and Air Conditioning. Did you complete the replacement? | -- | Go to Step 41 | -- | ||||||
37 | Replace the A/C high pressure switch. Refer to Air Conditioning (A/C) High Pressure Switch Replacement in Heating, Ventilation and Air Conditioning. Did you complete the replacement? | -- | Go to Step 41 | -- | ||||||
38 | Replace the A/C compressor clutch coil. Refer to Air Conditioning Clutch Coil Replacement in Heating, Ventilation and Air Conditioning. Did you complete the replacement? | -- | Go to Step 41 | -- | ||||||
39 | Replace the HVAC control assembly. Refer to Heater and Air Conditioning Control Replacement . Did you complete the replacement? | -- | Go to Step 41 | -- | ||||||
40 |
Important: Perform the programming procedure for the PCM. Replace the PCM. Refer to one of the following procedures:
Did you complete the replacement? | -- | Go to Step 41 | -- | ||||||
41 | Operate the system in order to verify the repair. Did you correct the condition? | -- | System OK | Go to Step 4 | ||||||
