B2438

Step 1: Perform visual inspection of the passenger seat belt buckle assembly and wiring harness from buckle to BCM, looking for pinched wires, damaged insulation, corrosion at connectors, or moisture intrusion. Pay special attention to areas where harness routes under seat tracks or near metal seat frame components.

Step 2: Disconnect the passenger seat belt buckle connector and measure resistance between the signal wire terminal (at harness side) and chassis ground using a digital multimeter. Reading should be infinite resistance (open circuit). If continuity to ground exists, the short is in the wiring harness between connector and BCM.

Step 3: With buckle connector still disconnected, measure resistance across the buckle switch terminals at the buckle side. Normal reading is open circuit (infinite resistance) when unbuckled and low resistance (typically less than 5 ohms) when buckled. If constant low resistance to ground exists in any position, replace the buckle assembly.

Step 4: Inspect BCM connector for corrosion, pushed-back pins, or moisture. Use electrical contact cleaner if needed. Reconnect all components, clear codes, and perform functional test by buckling and unbuckling passenger seat belt while monitoring live data for proper switch state changes.

Step 5: If short to ground persists after wiring and buckle verification, perform BCM voltage supply and ground circuit testing per manufacturer specifications. If BCM grounds and power supplies are correct but circuit still shows short, BCM replacement may be necessary.