Circuit/System Testing

Ignition OFF, disconnect the appropriate KR49 Headlamp Low Beam Relay, ignition ON
Verify a test lamp illuminates between the B+ circuit terminal 85 and ground.
- If the test lamp does not illuminate
  Replace the X50A Fuse Block - Underhood.
- If the test lamp illuminates
Verify a test lamp illuminates between the B+ circuit terminal 30 and ground.
- If the test lamp does not illuminate
  Replace the X50A Fuse Block - Underhood.
- If the test lamp illuminates
Connect a test lamp between the control circuit terminal 86 and B+, ignition ON.
Verify the test lamp turns ON and OFF when commanding the Low Beams 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.
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
Test or replace the appropriate KR49 Headlamp Low Beam Relay.