Circuit/System Testing

DTC B3948

1. Ignition OFF, disconnect the X5 harness connector at the K9 Body Control Module, ignition ON.
2. Verify a test lamp illuminates between the B+ circuit terminal 3 and ground.
   • If the test lamp does not illuminate and the circuit fuse is good 
   1. Ignition OFF, disconnect the harness connector at the X51A Fuse Block - Instrument Panel.
   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, disconnect the harness connector at the X51A Fuse Block - Instrument Panel.
   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 K9 Body Control Module.
   • Go to next step: If the test lamp illuminates 
3. Ignition OFF, connect the X5 harness connector at the K9 Body Control Module.
4. Ignition OFF, exterior lamps OFF, disconnect the harness connector at the appropriate component listed below.
   • E4LF Turn Signal Lamp - Left Front (Chevrolet)
   • E13LA Headlamp Assembly - Left Front (Buick)
   • A9A Outside Rearview Mirror - Driver (Buick)
5. Test for less than 10 Ω between the appropriate ground circuit terminal listed below and ground.
   • E4LF Turn Signal Lamp - Left Front socket terminal (Chevrolet)
   • E13LA Headlamp Assembly - Left Front terminal 8 (Buick)
   • A9A Outside Rearview Mirror - Driver terminal 5 (Buick with SGM)
   • A9A Outside Rearview Mirror - Driver terminal 9 (Buick with T4L)
   • 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.
   • Go to next step: If less than 10 Ω 
6. Connect a test lamp between the appropriate control circuit terminal listed below and ground, ignition ON.
   • E4LF Turn Signal Lamp - Left Front socket terminal
   • E13LA Headlamp Assembly - Left Front terminal 9 (Buick)
   • A9A Outside Rearview Mirror - Driver terminal 10 (Buick)
7. Verify the test lamp turns ON and OFF when commanding the Left Front Turn Signal Lamp ON and OFF with a scan tool.
   • If the test lamp is always OFF 
   1. Ignition OFF, disconnect the X5 harness connector at the K9 Body Control Module.
   2. Test for infinite resistance between the control circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • Go to next step: If infinite resistance
   3. 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 K9 Body Control Module.
   • If the test lamp is always ON 
   1. Ignition OFF, disconnect the X5 harness connector at the K9 Body Control Module, ignition ON.
   2. Test for less than 1 V between the control circuit terminal 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.
   • Go to next step: If the test lamp turns ON and OFF 
8. Test or replace the inoperative turn signal bulb.

DTC B3949

1. Ignition OFF, disconnect the X1 harness connector at the K9 Body Control Module, ignition ON.
2. Verify a test lamp illuminates between the B+ circuit terminal 3 and ground.
   • If the test lamp does not illuminate and the circuit fuse is good 
   1. Ignition OFF, disconnect the harness connector at the X51A Fuse Block - Instrument Panel.
   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, disconnect the harness connector at the X51A Fuse Block - Instrument Panel.
   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 K9 Body Control Module.
   • Go to next step: If the test lamp illuminates 
3. Ignition OFF, connect the X1 harness connector at the K9 Body Control Module.
4. Ignition OFF, exterior lamps OFF, disconnect the harness connector at the appropriate component listed below.
   • E4RF Turn Signal Lamp - Right Front (Chevrolet)
   • E13RA Headlamp Assembly - Right Front (Buick)
   • A9B Outside Rearview Mirror - Passenger (Buick)
5. Test for less than 5 Ω between the appropriate ground circuit terminal listed below and ground.
   • E4RF Turn Signal Lamp - Right Front socket terminal (Chevrolet)
   • E13RA Headlamp Assembly - Right Front terminal 8 (Buick)
   • A9B Outside Rearview Mirror - Passenger terminal 5 (Buick with SGM)
   • A9B Outside Rearview Mirror - Passenger terminal 9 (Buick with T4L)
   • If 5 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.
   • Go to next step: If less than 5 Ω 
6. Connect a test lamp between the appropriate control circuit terminal listed below and ground, ignition ON.
   • E4RF Turn Signal Lamp - Right Front socket terminal (Chevrolet)
   • E13RA Headlamp Assembly - Right Front terminal 9 (Buick)
   • A9B Outside Rearview Mirror - Passenger terminal 10 (Buick)
7. Verify the test lamp turns ON and OFF when commanding the Right Front Turn Signal Lamp ON and OFF with a scan tool.
   • If the test lamp is always OFF 
   1. Ignition OFF, disconnect the X4 harness connector at the K9 Body Control Module.
   2. Test for infinite resistance between the control circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • Go to next step: If infinite resistance
   3. 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 K9 Body Control Module.
   • If the test lamp is always ON 
   1. Ignition OFF, disconnect the X4 harness connector at the K9 Body Control Module, ignition ON.
   2. Test for less than 1 V between the control circuit terminal 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.
   • Go to next step: If the test lamp turns ON and OFF 
8. Test or replace the inoperative turn signal bulb.