GM Service Manual Online
For 1990-2009 cars only

Refer to Body Control Module Schematics (

Cell 51: DTC B2617 and B2618 -- Courtesy Lamp Circuit


Object Number: 465285  Size: FS
Cell 114: Headlamp Switch and HDLP SW, PARK LP Fuses
Cell 114: Inadvertent Power Relay, IP Compartment and Underhood Lamps
Cell 114: Inadvertent Power Relay, IP Compartment and Underhood Lamps
Cell 10: INT BATT, PWR LKS, CTSY LP and CIGAR LTR Fuses
Cell 114: CTSY LP Fuse, Courtesy Lamp Relay and Courtesy Lamps
Cell 117: Headlamp Switch
Body Control Module Components
Body Control System Circuit Description
Cell 117: ILLUM Fuse 12
Cell 14: G200, G201 and G207
Body Control System Connector End Views
Handling ESD Sensitive Parts Notice
).

Circuit Description

The BCM monitors the voltage and controls the ground of the courtesy lamp relay on CKT 690. The BCM will ground the relay and turn ON the courtesy lamps if either of the following conditions exists:

    • The BCM receives a signal from a mini-wedge door jamb switch.
    • The BCM receives an RFA signal to unlock the doors from the remote control door lock receiver module.
    • The courtesy lamp switch is turned ON.

Conditions for Setting the DTC

    • Any courtesy lamp input displays ACTIVE on the scan tool.
    • CKT 690 is shorted to battery voltage.
    • The system voltage is between 9.0-16.0 volts.
    • The above conditions exist for 0.5 seconds.

Action Taken When the DTC Sets

The courtesy lights will not operate.

Conditions for Clearing the MIL/DTC

    • This DTC will clear after the next operation of the courtesy lamps which does not contain a fault.
    • A history DTC will clear after 100 consecutive ignition cycles without a fault present.
    • History and current DTCs may be cleared using a scan tool.

Diagnostic Aids

       Important: Use the appropriate probe from the J 35616 connector test adapter kit for any probing of the fuse blocks or relay blocks in this table. Use of the appropriate probe prevents damage to the fuse blocks or relay blocks.

    • Always perform the first DTC that is listed on the scan tool if more than one DTC is displayed.
    • A scan tool gives Class 2 messages with the ignition switch in the RUN position.
    • Verify that the scan tool displays DTC B2618 as a current before you perform diagnostics.
    • Inspect for loose or poor connections at all of the related components.
    • Refer to Intermittents and Poor Connections Diagnosis in Wiring Systems.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. This step tests for a short to battery voltage in CKT 690.

  2. This step tests the courtesy lamp relay. Other DTCs will set when you disconnect the BCM connector.

  3. This step determines if CKT 690 is shorted to battery voltage.

Step

Action

Value(s)

Yes

No

1

Did you perform the BCM Diagnostic System Check?

--

Go to Step 2

Go to Diagnostic System Check - Body Control System

2

  1. Turn the ignition switch to the ON position.
  2. Open a door.
  3. Remove the courtesy lamp relay.
  4. Use the scan tool in order to monitor the current DTCs.

Does the scan tool display DTC B2618 as current?

--

Go to Step 3

Go to Step 5

3

  1. Use the scan tool in order to monitor the current DTCs.
  2. Disconnect the BCM connector C2 (LT BLU).

Does the scan tool display DTC B2618 as current?

--

Go to Step 4

Go to Step 6

4

Locate and repair the short to battery in CKT 690 (GRY/BLK) between the BCM connector C2 and the courtesy lamp relay (in the body relay block).

Is the repair complete?

--

Go to Step 7

--

5

Replace the courtesy lamp relay.

Is the repair complete?

--

Go to Step 7

--

6

  1. Replace the BCM.
  2. Program the correct calibrations into the BCM.
  3. Perform the learn procedure.

Is the repair complete?

--

Go to Step 7

--

7

Clear the DTCs.

Is the repair complete?

--

Go to Diagnostic System Check - Body Control System

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