Seat Belt Indicator Is On When Seat Belts Are Fastened

1. Turn ignition off. Disconnect IPC connector. Turn ignition on. Measure resistance between IPC connector terminal B4 and ground. See Figure . If resistance is less than 5 ohms, replace IPC. If resistance is greater than 5 ohms, go to next step.
2. Check Yellow wire between Standard Body Module (SBM) connector C2 terminal A4 and IPC cluster connector terminal B4 for an open. See Figure and Fig 1 . If an open in Yellow wire exists, locate and repair as necessary. If an open does not exist, replace SBM with a known good unit and retest. If system operates as designed, replace Standard Body Module.

Fig 1: Identifying Standard Body Module (SBM) Connectors & Terminals

Courtesy of GENERAL MOTORS CORP.