FixVault

Circuit/System Testing

Driver Window Switch Malfunction

  1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the S79D window switch-driver. 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 1 and ground.
    • 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. Verify a test lamp illuminates between the B+ circuit terminal 4 and ground.
    • 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
    3. Test for infinite resistance between the signal circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance, replace the S79D window switch-driver
    • If the test lamp illuminates 
  4. Test for 5-10 V between the serial data circuit terminal 5 and ground
    • If less than 5 V 
    1. Ignition OFF, disconnect the harness connector at the K9 body control module.
    2. Test for infinite resistance between the serial data and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance
    3. Test for less than 2 Ω in the serial data circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance on the circuit.
      • If less than 2 Ω, replace the K9 body control module.
    • If greater than 10 V 
    1. Ignition OFF, disconnect the harness connector at the K9 body control module, ignition ON.
    2. Test for less than 1 V between the serial data signal circuit and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • If less than 1 V, replace the K9 body control module.
    • If between 5-10 V 
  5. Test or replace the S79D window switch-driver.

Rear Power Window Inoperative

  1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the appropriate rear M74 window motor. 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 1 and ground.
    • 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 2 and ground.
    • 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
    3. Test for infinite resistance between the signal circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance, replace the rear M74 window motor.
    • If the test lamp illuminates 
  5. Test for 5-10 V between the serial data circuit terminal 4 and ground
    • If less than 5 V 
    1. Ignition OFF, disconnect the harness connector at the K9 body control module.
    2. Test for infinite resistance between the serial data and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance
    3. Test for less than 2 Ω in the serial data circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance on the circuit.
      • If less than 2 Ω, replace the K9 body control module.
    • If greater than 10 V 
    1. Ignition OFF, disconnect the harness connector at the K9 body control module, ignition ON.
    2. Test for less than 1 V between the serial data circuit and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • If less than 1 V, replace the K9 body control module.
    • If between 5-10 V 
  6. Replace the rear M74 window motor.