Bus +/- Signals Open Or No Response From Body Control Module

Possible Causes:

• Open Ground Circuit At The Junction Block Connector C2
• Open Ground Circuit At The Junction Block Connector C3
• Open Fused B+ Circuit (Junction Block)
• Open Ground Circuit At The Junction Block Body Control Module Conn Cav 1
• Open Ground Circuit At The Junction Block Body Control Module Conn Cav 20
• Body Control Module

Testing

1. Turn ignition off. Disconnect junction block connector C2. See Figure . Measure resistance between ground and junction block connector C2 terminal No. 8, ground circuit (Black/Orange wire). See Figure . If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Black/Orange wire.
2. Disconnect junction block connector C3. Measure resistance between ground and junction block connector C3 terminal No. 4, ground circuit (Black/Light Green wire). See Figure . If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Black/Light Green wire.
3. Ensure ignition is off. Remove Body Control Module (BCM) from back of junction block. Using a 12-volt test light connected to ground, probe terminal No. 7, fused B+ circuit at BCM connector on back of junction block. If test light illuminates, leave BCM removed and go to next step. If test light does not illuminate, replace junction block. See JUNCTION BLOCK  under REMOVAL & INSTALLATION.
4. Connect junction block connector C2. Measure resistance between ground and terminal No. 1, ground circuit at BCM connector on back of junction block. If resistance is less than 5 ohms, leave BCM removed and go to next step. If resistance is 5 ohms or more, replace junction block. See JUNCTION BLOCK  under REMOVAL & INSTALLATION.
5. Connect junction block connector C3. Measure resistance between ground and terminal No. 20, ground circuit at BCM connector on back of junction block. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, replace junction block. See JUNCTION BLOCK  under REMOVAL & INSTALLATION.
6. Disconnect BCM connector C1. Measure resistance between ground and Data Link Connector (DLC) terminal No. 2, PCI bus circuit (Violet/Yellow wire). See Figure . If resistance is more than 100 ohms, go to next step. If resistance is 100 ohms or less, repair short to ground in Violet/Yellow wire.
7. Turn ignition on. Measure voltage on DLC terminal No. 2, PCI bus circuit (Violet/Yellow wire). If voltage does not exist, go to next step. If voltage exists, repair short to voltage in Violet/Yellow wire.
8. Measure resistance in PCI bus circuit (Violet/Yellow wire) between DLC terminal No. 2 and BCM connector C1 terminal No. 14. See Figure and Figure . If resistance is less than 5 ohms, replace BCM. See BODY CONTROL MODULE  . If resistance is 5 ohms or more, repair open in Violet/Yellow wire.