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Circuit/System Testing

  1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the appropriate S79 Window Switch. It may take up to 2 minutes for all vehicle systems to power down.
  2. Test for less than 10 Ω between the ground circuit terminal listed below and ground:
    • S79D Window Switch-Driver - ground circuit terminal 1
    • S79P Window Switch-Passenger - ground circuit terminal 1
    • S79LR Window Switch-Left Rear - ground circuit terminal 5
    • S79RR Window Switch-Right Rear - ground circuit terminal 5
    • If 10 Ω or greater 
    1. Ignition OFF.
    2. Test for less than 2 Ω in the ground circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, repair the open/high resistance in the ground connection.
    • If less than 10 Ω 
  3. Ignition ON.
  4. Verify a test lamp illuminates between the B+ circuit terminal listed below and ground:
    • S79D Window Switch-Driver - B+ circuit terminal 4
    • S79P Window Switch-Passenger - B+ circuit terminal 4
    • S79LR Window Switch-Left Rear - B+ circuit terminal 8
    • S79RR Window Switch-Right Rear - B+ circuit terminal 8
    • If the test lamp does not illuminate and the circuit fuse is good 
    1. Ignition OFF.
    2. Test for less than 2 Ω in the B+ circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, verify the fuse is not open and there is voltage at the fuse.
    • If the test lamp does not illuminate and the circuit fuse is open 
    1. Ignition OFF.
    2. Test for infinite resistance between the B+ circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance, replace the S79 Window Switch.
    • If the test lamp illuminates 
  5. Ignition OFF connect the harness connector at the S79 Window Switch and disconnect the harness connector at the M74 Window Motor.
  6. Test for less than 5 Ω between the control circuit terminal A and ground.
    • If 5 Ω or greater 
    1. Ignition OFF, disconnect the harness connector at the S79 Window Switch.
    2. Test for less than 2 Ω in the control circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, replace the S79 Window Switch.
    • If less than 5 Ω 
  7. Test for less than 5 Ω between the control circuit terminal B and ground.
    • If 5 Ω or greater 
    1. Ignition OFF, disconnect the harness connector at the S79 Window Switch.
    2. Test for less than 2 Ω in the control circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, replace the S79 Window Switch.
    • If less than 5 Ω 
  8. Connect a test lamp between the control circuit terminal A and control circuit terminal B, ignition ON.
  9. Verify the test lamp illuminates when commanding the UP and DOWN states with the S79 Window Switch.
    • If the test lamp does not illuminate during either of the commands 
    1. Ignition OFF, disconnect the harness connector at the S79 Window Switch.
    2. Test for infinite resistance between each control circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance, replace the S79 Window Switch.
    • If the test lamp illuminates during each of the commands 
  10. Test or replace the M74 Window Motor.
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