Circuit/System Testing

Verify that a test lamp illuminates between the G13 generator B+ terminal + X2 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 greater than 100 Ω between the B+ circuit and ground.
  - If 100 Ω or less, repair the short to ground on the circuit.
  - If greater than 100 Ω, replace the generator.
- If the test lamp illuminates
Ignition OFF, disconnect the X1 harness connector at the generator, engine Running, command the Generator L-Terminal Command ON with a scan tool.
Test for 3.5V or greater between the control circuit terminal listed below and ground.
- Terminal A X1 (LMU and LDT Engine)
- Terminal B X1 (L95, LXV, LXT, and LXV Engine)
- If less than 3.5V
1. Ignition OFF, disconnect the harness connectors at the ECM.
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 greater the 2 Ω, repair the open/high resistance in the circuit.
  - If less than 2 Ω, replace the ECM.
- If 3.5V or greater
1. Ignition OFF, disconnect the harness connectors at the ECM.
2. Test for less than 1 V between the control circuit and ground.
  - If less than 1 V, replace the Generator.
  - If 1 V or greater, repair the short to voltage on the circuit.