B1852

Step 1: Visually inspect the temperature differential sensor location and wiring harness for obvious damage, chafing, pinched wires, or evidence of water intrusion. Check connector for corrosion, pushed-back pins, or moisture.

Step 2: Disconnect the temperature differential sensor connector and measure resistance between the sensor signal wire terminal (at harness side) and vehicle ground using a multimeter. Reading should be infinite ohms (open circuit); any measurable resistance confirms a short to ground in the wiring.

Step 3: If wiring tests good, measure resistance across the temperature sensor itself (disconnected). Compare readings to manufacturer specifications (typically 2k-10k ohms depending on temperature). If sensor shows 0 ohms or very low resistance, sensor has internal short to ground.

Step 4: Inspect the entire wiring harness route from sensor to climate control module, focusing on areas where harness passes through firewalls, near brackets, or along sharp metal edges. Use wiggle test while monitoring resistance to ground to isolate intermittent shorts.

Step 5: If no shorts found in wiring or sensor, inspect climate control module connector for corrosion, terminal tension, or backed-out pins. Measure resistance from module-side connector terminal to ground with module disconnected to verify module is not internally shorted.

Step 6: After repair, clear codes and operate climate control system through all temperature ranges and zones. Monitor live data to confirm temperature differential sensor provides proper varying voltage signal (typically 0.5-4.5V) with no return of short circuit fault.