2010 Cadillac Truck Escalade AWD V8-6.2L Page 1002
compressor relay fault is detected, the ESCM retries the output every 15 seconds to try to recover from the fault.
Reference Information
Schematic Reference
Automatic Level Control Schematics (See: Steering and Suspension/Suspension/Suspension Control ( Automatic - Electronic
)/Diagrams/Electrical Diagrams/Automatic Level Control)
Connector End View Reference
Component Connector End Views (See: Diagrams/Connector Views)
Description and Operation
Automatic Level Control Description and Operation (See: Steering and Suspension/Suspension/Suspension Control ( Automatic - Electronic
)/Description and Operation/Automatic Level Control Description and Operation)
Electrical Information Reference
* Circuit Testing (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic Procedures/Circuit
Testing/Circuit Testing)
* Connector Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic
Procedures/Connector Repairs/Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (See: Testing and Inspection/Component Tests and General Diagnostics/General
Electrical Diagnostic Procedures/Circuit Testing/Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic Procedures/Wiring
Repairs/Wiring Repairs)
Scan Tool Reference
Control Module References (See: Testing and Inspection/Programming and Relearning)for Scan Tool Information
Circuit/System Verification
Ignition ON, command the compressor relay ON with a scan tool. Listen for the operation of the ALC relay and the automatic level control
compressor.
Circuit/System Testing
1. Ignition OFF, disconnect the ALC relay.
2. Ignition ON, verify that a test lamp does not illuminate between the relay connector control circuit terminal 86 and ground.
锟斤拷If the test lamp illuminates, test the control circuit for a short to voltage.
3. Verify that a test lamp illuminates between the relay connector B+ circuit terminal 85 and ground.
锟斤拷If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the
B+ circuit fuse is open, test the relay coil B+ circuit for a short to ground. If all circuits test normal, test or replace the ELC relay.
4. Verify that a test lamp illuminates between the relay connector B+ circuit terminal 30 and ground.
锟斤拷If the test lamp does not illuminate, test the B+ circuit for an open/high resistance. If the circuit tests normal and the B+ circuit fuse is
open, test the relay coil B+ circuit and compressor control circuit for a short to ground or a faulty ALC compressor motor. If all circuits
test normal, test or replace the ELC relay.
5. Disconnect the harness connector at the air compressor.
6. Test for less than 1 ohm of resistance between the ALC compressor ground circuit terminal G and ground.
锟斤拷If greater than 1 ohm, test the ground circuit for an open/high resistance.
7. Connect the harness connector at the ALC compressor.
8. Connect a 40-A fused jumper wire between the relay connector B+ circuit terminal 30 and the relay connector control circuit terminal 87.
Verify the ALC compressor is activated.
锟斤拷If the ALC compressor does not activate, test the control circuit for an open/high resistance. If the circuit tests normal, test or replace the
ALC compressor.
9. Connect a test lamp between the relay connecor B+ circuit terminal 85 and the relay connector control circuit terminal 86.
10. Command the ALC compressor relay ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the
commanded states.
锟斤拷If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the electronic suspension
