LEMON Manuals: Even more car manuals for everyone
Home >> Chevrolet >> 2011 >> Chevy Express H1500, Van Cargo >> Repair and Diagnosis >> External Pages >> Different car >> Section 1764 (Engine Cooling System) >> Diagnostic Information and Procedures >> DTC P0480 >> Circuit/System Testing

Circuit/System Testing

WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2010 GMC Savana Special, 2010 GMC Savana Camper Special, 2010 GMC Savana, 2010 Chevrolet RV Cutaway, and 2010 Chevrolet Cutaway. However, it is still accessible from the selected car via links, so may be relevant.
  1. Ignition OFF, disconnect the cooling fan or fan clutch relay.
  2. Test for less than 3 Ω between the fan relay ground circuit terminal K9, or relay terminal 6 and ground.
    • If greater than the specified range, test the ground circuit for an open/high resistance.
  3. Operate the engine at 1,500 RPM for 2 minutes. The fan should be quiet to indicate the clutch is disengaged.
    • If not disengaged, test the cooling fan clutch supply voltage circuit for a short to voltage. If the circuit tests normal, replace the clutch.
  4. Ignition OFF, connect a 10 A fused jumper wire between the cooling fan clutch supply voltage circuit terminal K11, or relay terminal 4 and B+.
  5. Operate the engine at 1,500 RPM for 2 minutes. The fan should be loud to indicate the clutch is engaged.
    • If not engaged, test the cooling fan clutch supply voltage circuit for a short to ground or an open/high resistance. If the circuit tests normal, test the fan clutch ground circuit for an open/high resistance. If the circuits test normal, replace the fan clutch.
  6. Ignition OFF, connect a 10 A fused jumper wire between the relay voltage supply circuit terminal J12, relay terminal 2, and the cooling fan clutch supply voltage circuit terminal K11, relay terminal 4.
  7. Operate the engine at 1,500 RPM for 2 minutes. The fan should be loud to indicate the clutch is engaged.
    • If not engaged, test the relay voltage supply circuit for a short to ground or an open/high resistance. If the circuit tests normal and the fuse is open, test all the components connected to the fuse and replace as necessary.
  8. Ignition OFF, connect a test lamp between the cooling fan clutch relay control circuit terminal L12, relay terminal 5 and B+. The test lamp should not illuminate.
    • If the test lamp illuminates, test the control circuit for a short to ground.
  9. Engine operating at 1,500 RPM, command the cooling fan clutch to 80 percent for 2 minutes, with a scan tool. The test lamp should illuminate or flash, indicating that the ECM can control the relay.
    • If the lamp does not illuminate or flash, test the cooling fan clutch control circuit for an open/high resistance, or for a short to voltage. If the circuit tests normal, replace the ECM.
  10. If all circuits and the ECM test normal, replace the relay.
scientia non olet · About LEMON Manuals