Circuit/System Testing

Daytime Running Lamp Malfunction - with T4F

1. Ignition OFF, exterior lamps OFF, disconnect the harness connector at the appropriate E4 daytime running lamp.
2. Test for less than 5 Ω between the ground circuit terminal 2 and ground.
   • 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.
   • If less than 5 Ω 
3. Connect a test lamp between the control circuit terminal 1 and ground, ignition ON.
4. Verify the test lamp turns ON and OFF when commanding the Dedicated Daytime Running Lamp Command 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.
      • 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.
   • If the test lamp turns ON and OFF 
5. Test or replace the appropriate E4 daytime running lamp.

Daytime Running Lamp Malfunction - with T4A

1. Ignition OFF, disconnect the X2 harness connector at the X50A fuse block - underhood.
2. Connect a test lamp between the control circuit terminal 19 and B+, ignition ON.
3. Verify the test lamp turns ON and OFF when commanding the Front Fog Lamps 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, 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
   3. Ignition OFF.
   4. 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 infinite resistance between the control circuit terminal and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance, replace the K9 body control module.
   • If the test lamp turns ON and OFF 
4. Ignition OFF, connect the X2 harness connector at the X50A fuse block - underhood.
5. Ignition OFF, exterior lamps OFF, disconnect the harness connector at the E4C daytime running lamp - left.
6. Test for less than 5 Ω between the ground circuit terminal 2 and ground.
   • 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.
   • If less than 5 Ω 
7. Connect a test lamp between the control circuit terminal 1 and ground, ignition ON.
8. Verify the test lamp turns ON and OFF when commanding the Front Fog Lamps ON and OFF with a scan tool.
   • If the test lamp is always OFF 
   1. Ignition OFF, disconnect the X1 harness connector at the X50A fuse block - underhood.
   2. Test for infinite resistance between the control circuit 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 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 X50A fuse block - underhood.
   • If the test lamp is always ON 
   1. Ignition OFF, disconnect the X1 harness connector at the X50A fuse block - underhood, ignition ON.
   2. Test for less than 1 V between the control circuit and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • If less than 1 V, replace the X50A fuse block - underhood.
   • If the test lamp turns ON and OFF 
9. Test or replace the appropriate E4 daytime running lamp.