LEMON Manuals: Even more car manuals for everyone
Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 1811 (Fixed And MOVEABLE Windows) >> Diagnostic Information and Procedures >> Rear Window Defogger Inoperative >> Circuit/System Testing >> Rear Defogger Switch Malfunction

Rear Defogger Switch Malfunction

WARNING: This page is about a different car, the 2007 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.
  1. Ignition OFF, disconnect the harness connector C1 at the HVAC Module.
  2. Ignition OFF, test for less than 1.0 ohm of resistance between the ground circuit terminal 12 and ground.
    • If greater than the specified range, test the ground circuit for an open/high resistance.
  3. Ignition ON, verify the scan tool BCM Rear Defog Switch parameter if OFF.
    • If not the specified value, test the signal circuit terminal 1 for a short to ground. If the circuit tests normal, replace the BCM.
  4. Install a 3 A fused jumper wire between the signal circuit terminal 1 and ground. Verify the scan tool BCM Rear Defog Switch parameter is ON.
    • If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
  5. If all circuits test normal, test or replace the HVAC module.
scientia non olet · About LEMON Manuals