B2514

Step 1: Perform visual inspection of blower motor wiring harness from BCM to blower motor, checking for chafed, melted, or damaged insulation particularly near sharp edges, firewall pass-throughs, and moving components. Look for signs of heat damage or previous repair attempts.

Step 2: Disconnect blower motor connector and measure voltage at blower motor supply wire with ignition on and blower switch off using a digital multimeter. Reading should be 0V; presence of battery voltage (12-14V) confirms short to Vbatt upstream of motor.

Step 3: Disconnect blower motor resistor/power module and retest circuit. If voltage disappears, resistor module is shorted internally. If voltage remains, continue tracing wiring harness toward BCM for pinch points or shorts to nearby power sources.

Step 4: Check blower motor relay operation by removing relay and testing for continuity between power terminals with relay de-energized (should be open circuit). If continuity exists, relay is stuck closed. Also inspect relay socket terminals for corrosion or crossed pins.

Step 5: If all external components test normal, check blower motor itself by measuring resistance between motor terminals (should be 2-10 ohms typically) and between each terminal and motor housing ground (should be infinite resistance/open circuit).

Step 6: After repair, clear codes, operate blower motor through all speed settings, and verify proper operation with no voltage present on circuit when blower is commanded off. Monitor for code return during test drive with climate control cycling.