B1532

Step 1: Perform visual inspection of the DIC switch assembly on the steering wheel or dash for physical damage, wear, or sticking buttons. Check for aftermarket modifications or steering wheel swaps that may affect switch operation.

Step 2: Using a digital multimeter, backprobe the DIC switch connector and verify 5V or 12V reference voltage (manufacturer-dependent) is present at the switch supply pin with ignition on. Check for proper ground continuity (less than 0.5 ohms to chassis ground).

Step 3: Test switch resistance by measuring between signal and ground pins while pressing each DIC button. Each button should produce a unique resistance value per manufacturer specifications (typically ranging from 0 to 10,000 ohms in stepped increments). Compare readings to factory service data.

Step 4: Inspect the wiring harness from the switch to the BCM connector for chafing, pinching, water intrusion, or corrosion. Pay special attention to areas where harness flexes near steering column or passes through firewall. Perform continuity tests on all circuit wires.

Step 5: Disconnect the BCM connector and measure resistance from BCM terminals to ground with switch unplugged. Infinite resistance indicates no short; low resistance indicates short to ground. With switch connected, verify proper signal voltage changes when buttons are pressed.

Step 6: If all circuits test normal, perform BCM output test using scan tool bidirectional controls to command BCM functions. Replace BCM if unable to process DIC switch inputs or if other BCM-related codes are present.