Diagnostic Procedures
WARNING: This page is about a different car, the 1999 GMC Sierra and 1999 Chevrolet Silverado. However, it is still accessible from the selected car via links, so may be relevant.
- If BCM diagnostic system check has been performed, go to next step. If BCM diagnostic system check has not been performed, perform BCM diagnostic system check. See BCM DIAGNOSTIC SYSTEM CHECK under SYSTEM TESTS.
- Using scan tool, monitor current DTCs. Disconnect Purple BCM connector C3. If scan tool displays DTC B2973 as current, go to step 8 . If scan tool does not display DTC B2973 as current, go to next step.
- Using test light connected to battery voltage, backprobe Purple BCM connector C3 terminal B3 (Light Green wire). See Figure . Disconnect left front door jamb switch while observing test light. If test light illuminates, leave test light connected and go to next step. If test light does not illuminate, go to step 6 .
- With test light still connected between battery voltage and Purple BCM connector C3 terminal B3, disconnect right front door jamb switch. If test light illuminates, go to step 7 . If test light does not illuminate, go to next step.
- Replace right front door jamb switch. After repair, go to step 9 .
- Replace left front door jamb switch. After repair, go to step 9 .
- Locate and repair short to ground in Light Green wire between Purple BCM connector C3 terminal B3 and left or right front door jamb switch. See WIRING DIAGRAMS . After repair, go to step 9 .
- Replace BCM and program. See BODY CONTROL MODULE (BCM) under REMOVAL & INSTALLATION.
- Reconnect all components. Clear DTCs. See CLEARING DIAGNOSTIC TROUBLE CODES (DTCS) under SELF-DIAGNOSTIC SYSTEM.