B1212

Step 1: Perform visual inspection of all wiring harnesses between the steering wheel switch assembly and BCM, checking for chafing, pinching, or damage at common wear points (steering column, door jambs, under dash). Look for exposed copper wire or melted insulation.

Step 2: Disconnect the EIC Switch-2 connector at the steering wheel or instrument cluster. Using a digital multimeter, measure resistance between the switch signal wire (identified in vehicle-specific wiring diagram) and ground with switch disconnected. Reading should be infinite (OL); any measurable resistance indicates wiring harness short.

Step 3: If harness tests good, measure resistance across the switch terminals with switch disconnected and in various positions. Compare readings to manufacturer specifications. Internal short will show near-zero ohms to ground terminal in all positions.

Step 4: Inspect all connectors in the circuit for corrosion, pushed-back pins, or moisture intrusion. Clean contacts with electrical contact cleaner and apply dielectric grease. Wiggle connectors while monitoring for intermittent shorts.

Step 5: If all wiring and switches test normally, perform BCM voltage supply test to verify proper reference voltage output on the switch circuit (typically 5V or 12V). Low or absent voltage may indicate BCM internal fault.

Step 6: After repair, clear codes and perform function test of all EIC switch operations. Road test vehicle and verify code does not return using freeze frame data and continuous monitoring.