GM Service Manual Online
For 1990-2009 cars only

Diagnostic Instructions

    • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
    • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
    •  Diagnostic Procedure Instructions provides an overview of each diagnostic category.

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

Reading Lamps B+

1, 2, 3

1

--

--

Reading Lamps Ground Terminal 6

--

1

--

--

1. Reading lamps always Off

2. Sunshade lamps always Off

3. I/P Compartment lamp Always Off

Circuit/System Description

The body control module (BCM) supplies the the dome/reading lamps, sunshade and I/P compartment lamp with battery voltage. When switching on the following components the concerning lamps will illuminate:

    • Dome/reading lamps
    • Dome/reading lamps - row
    • Sunshade - left Front
    • Sunshade - right Front
    • I/P compartment lamp

Reference Information

Schematic Reference

Interior Lights Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Interior Lighting Systems Description and Operation

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

Ignition ON, switch the dome/reading lamps or dome/reading lamps - row ON and OFF while observing the lamp. The concerning reading lamp should illuminate when switched ON.

Circuit/System Testing

Reading Lamps Circuit Malfunction

  1. Ignition OFF, disconnect the harness connector at the E37A Dome/Reading Lamps or E37B Dome/Reading Lamps - Row.
  2. Test for less than 5 Ω between the ground circuit terminal 6 and ground.
  3. If greater than the specified range, test the ground circuit for an open/high resistance.
  4. Ignition ON, test for greater than 11 V between the circuit terminal 1 and the ground circuit terminal B.
  5. If less than the specified range, test the circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K9 Body Control Module (BCM).
  6. If all circuits test normal, test or replace the E37A Dome/Reading Lamps or E37B Dome/Reading Lamps - Row.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Reading Lamp Bulb Replacement
    •  Reading Lamp Replacement
    •  Dome and Reading Lamp Replacement
    •  Dome and Reading Lamp Lens Replacement
    •  Control Module References for BCM replacement, setup, and programming