2010 Cadillac Truck Escalade/ESV RWD V8-6.2L Page 2207

2010 Cadillac Truck Escalade/ESV RWD V8-6.2L Page 2207

瀚慖f the test lamp does not illuminate, test the ignition circuit for a short to ground or a open/high resistance. If the circuit tests normal and

ignition circuit fuse is open, test all components connected to the ignition circuit and replace as necessary.

4. Verify that a test lamp illuminates between the relay B+ circuit terminal 30 and ground.

瀚慖f the test lamp does not illuminate, test the B+ circuit for a short to ground or a open/high resistance. If the circuit tests normal and B+

circuit fuse is open, replace the A/C clutch relay.

5. Disconnect the harness connector at the A/C clutch coil.

6. Test for less than 1 ohm between the ground circuit terminal 2 and ground.

瀚慖f greater than the specified range, test the ground circuit for an open/high resistance.

7. Connect the harness connector at the A/C clutch coil.

8. Connect a 10-amp fused jumper wire between the B+ circuit terminal 30 and control circuit terminal 87. Verify the A/C clutch is activated.

瀚慖f the A/C clutch does not activate, test the control circuit for an open/high resistance. If the circuit tests normal, test or replace the A/C

clutch.

9. Connect a test lamp between the ignition circuit terminal 85 and the control circuit terminal 86.

10. Command the A/C relay output function ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the

commanded states.

瀚慖f the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the ECM.

瀚慖f the test lamp is always OFF, test the control circuit for a short to voltage, or an open/high resistance. If the circuit tests normal, replace

the ECM.

11. If all circuits test normal, test or replace the A/C clutch relay.

Component Testing

1. Ignition OFF, disconnect the A/C COMP relay.

2. Test for 60-180 ohms between terminals 85 and 86.

瀚慖f the resistance is not within the specified range, replace the relay.

3. Test for infinite resistance between the following terminals:

* 30 and 86

* 30 and 87

* 30 and 85

* 85 and 87

瀚慖f not the specified value, replace the relay.

4. Install a 30-amp fused jumper wire between relay terminal 85 and 12 volts. Install a jumper wire between relay terminal 86 and ground. Test

for less than 2 ohms between terminals 30 and 87.

瀚慖f greater than the specified range, replace the relay.

Repair Instructions

Perform the Diagnostic Repair Verification (See: Verification Tests) after completing the diagnostic procedure.

* Relay Replacement (Attached to Wire Harness) (See: Power and Ground Distribution/Power Distribution Relay/Service and Repair/Relay

Replacement (Attached to Wire Harness))Relay Replacement (Within an Electrical Center) (See: Power and Ground Distribution/Power

Distribution Relay/Service and Repair/Relay Replacement (Within an Electrical Center))

* Control Module References (See: Testing and Inspection/Programming and Relearning) for ECM replacement, setup, and programming

HVAC - Automatic

DTC P0645

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic System

Check - Vehicle) prior to using this diagnostic procedure.

* Review Strategy Based Diagnosis (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Strategy Based Diagnosis) for an

overview of the diagnostic approach.