Pinpoint Test B: The Courtesy Lamps Do Not Illuminate With the Liftgate Open

Interior Lighting

Pinpoint Test B: The Courtesy Lamps Do Not Illuminate With the Liftgate Open

Refer to Wiring Diagrams Set 117, Remote Keyless Entry and Alarm for schematic and connector information. Electrical Diagrams

Normal Operation

When the liftgate is opened, the liftgate ajar switch (or Liftgate/Trunk Module (LTM), if equipped) opens the ground signal to the Smart Junction Box (SJB). The SJB (Smart Junction Box) monitors the liftgate ajar circuit, and based on the ajar status, supplies voltage to the courtesy lamps.

- DTC B2721 (Liftgate/Decklid Ajar Output Short To Ground Or Open)- a continuous and on-demand DTC that sets when the LTM (Liftgate/Trunk Module) detects a short to ground from the liftgate ajar input circuit to the SJB (Smart Junction Box).

This pinpoint test is intended to diagnose the following:

- Wiring, terminals or connectors

- Liftgate ajar switch (part of the liftgate latch)

- LTM (Liftgate/Trunk Module)

- SJB (Smart Junction Box)

PINPOINT TEST B : THE COURTESY LAMPS DO NOT ILLUMINATE WITH THE LIFTGATE OPEN

NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.

B1 CHECK THE LTM (Liftgate/Trunk Module) OR THE LIFTGATE LATCH

- Ignition OFF.

- Disconnect: LTM (Liftgate/Trunk Module) C4174A or Liftgate Ajar Switch C4185.

Do the courtesy lamps illuminate?

Yes
If equipped with a power liftgate, GO to B4.

If equipped with a manual liftgate, INSTALL a new liftgate latch. TEST the system for normal operation.

No
GO to B2.

B2 CHECK THE LIFTGATE AJAR INPUT CIRCUIT FOR A SHORT TO GROUND

- Disconnect: SJB (Smart Junction Box) C2280C.

- Measure the resistance between the SJB (Smart Junction Box) C2280C-16, circuit CPL58 (GY/OG), harness side and ground.





Is the resistance greater than 10,000 ohms?

Yes
GO to B3.

No
REPAIR circuit CPL58 (GY/OG) for a short to ground. CLEAR the DTCs. REPEAT the self-test.

B3 CHECK FOR CORRECT SJB (Smart Junction Box) OPERATION

- Disconnect all the SJB (Smart Junction Box) connectors.

- Check for:
- corrosion

- damaged pins

- pushed-out pins


- Connect all the SJB (Smart Junction Box) connectors and make sure they seat correctly.

- Operate the system and verify the concern is still present.

Is the concern still present?

Yes
INSTALL a new SJB (Smart Junction Box). TEST the system for normal operation.

No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.

B4 CHECK FOR CORRECT LTM (Liftgate/Trunk Module) OPERATION

- Disconnect all the LTM (Liftgate/Trunk Module) connectors.

- Check for:
- corrosion

- damaged pins

- pushed-out pins


- Connect all the LTM (Liftgate/Trunk Module) connectors and make sure they seat correctly.

- Operate the system and verify the concern is still present.

Is the concern still present?

Yes
INSTALL a new LTM (Liftgate/Trunk Module). TEST the system for normal operation.

No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.