2010 Cadillac Truck Escalade RWD V8-6.0L Hybrid Page 627
When the Headlamp and Panel Dimmer Switch is placed in the headlamp ON position, ground is applied to the body control module (BCM)
through the headlamp low beam signal circuit. The BCM then applies ground to the HDLP LO/HID Relay control circuit which energizes the low
beam relay. With the low beam relay energized, the switch contacts close allowing B+ to flow through the LOW HDLP fuses to the low beam
headlamps.
Conditions for Running the DTC
* Battery voltage must be between 9-16 V.
* Headlamps must be ON.
Conditions for Setting the DTC
The BCM detects a short to voltage in the headlamp low beam relay control circuit.
Actions Taken When the DTC Sets
The low beam headlamps will not operate.
Conditions for Clearing the DTC
* The condition responsible for setting the DTC no longer exists.
* A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.
Reference Information
Schematic Reference
Headlights/Daytime Running Lights (DRL) Schematics (See: Diagrams/Electrical Diagrams/Lighting and Horns/System
Diagram/Headlights/Daytime Running Lights (DRL) Schematics)
Connector End View Reference
Component Connector End Views (See: Diagrams/Connector Views)
Description and Operation
Exterior Lighting Systems Description and Operation (See: Lighting and Horns/Description and Operation/Exterior Lighting Systems 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 Testing
1. Ignition OFF, disconnect the low beam headlamp relay.
2. Ignition ON, verify that a test lamp does not illuminate between the control circuit terminal 87 and ground.
瀚慖f the test lamp illuminates, test the control circuit for a short to voltage.
3. Verify that a test lamp illuminates between the B+ circuit terminal 85 and ground.
瀚慖f 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 control circuit terminal 87 for a short to ground. If the circuit tests normal, test or replace the low beam
headlamp relay.
4. Verify that a test lamp illuminates between the B+ circuit terminal 30 and ground.
瀚慖f the test lamp does not illuminate, test the B+ circuit for an open/high resistance.
5. Disconnect the harness connector at the appropriate head lamp.
6. Test for less than 5 ohm between the head lamp ground circuit terminal listed below and ground:
