Rear Multifunction Carrier Malfunction - D8G

Rear Multifunction Carrier Malfunction - D8G

Diagnostic Instructions

Diagnostic Fault Information

Circuit/System Description

The headlamp switch is supplied with ground at all times. When the headlamp switch is placed in either the park or dipped beam position, ground is applied to the tail lamp signal circuit to the body control module (BCM). The BCM sends this message to the trailer lighting converter. The trailer lighting converter then applies a voltage to the appropriate trailer tail lamp through there respective voltage supply circuits.

Reference Information

Schematic Reference

Trailer Connector/Provision Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Exterior Lighting Systems Description and Operation

Electrical Information Reference

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

1. If none of the multifunction carrier lamps function properly, refer to Rear Multifunction Carrier Malfunction.
2. Command the Trailer Tail Lamps test with a scan tool. The tail lamps should turn ON and OFF when changing between the commanded states.

⇒	If the tail lamps are always ON or OFF, refer to DTC B3885 or B3886 .

3. Command the Trailer Indicator Lamps test with a scan tool. The indicator lamps should turn ON and OFF when changing between the commanded states.

⇒	If the appropriate indicator is always ON or OFF, refer to DTC B3887 or B3888 .

4. Command the Trailer Brake Lamps test with a scan tool. The brake lamps should turn ON and OFF when changing between the commanded states.

⇒	If the brake lamps are always ON or OFF, refer to DTC B3889 .

5. Command the Trailer Backup Lamps Active/Inactive test with a scan tool. The reversing lamp should turn ON and OFF when changing between the commanded states.

⇒	If the back up lamp are always ON or OFF, refer to DTC B3890 .

6. Command the Trailer Fog Lamp(s) Active/Inactive test with a scan tool. The fog lamp should turn ON and OFF when changing between the commanded states.

⇒	If the back up lamp are always ON or OFF, refer to DTC B3891 .

Circuit/System Testing

Rear Multifunction Carrier Malfunction

1. Install the rear multifunction carrier system.
2. Ignition ON and switch ON the headlamps.
3. Move a magnet in front of the reed switch. The tail lamps should be OFF.

⇒	If the tail lamps are ON replace the or reed switch or K68 Trailer Lighting Control Module.

4. Remove the magnet, the tail lamps should be OFF.

⇒	If the tail lamps are OFF replace the or reed switch or K68 Trailer Lighting Control Module.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for trailer lighting converter replacement, setup and programming