Circuit/System Testing

Verify that a test lamp illuminates between the G13 Generator B+ circuit terminal A X1, A X2 (LYX), AX2 (LH7/LTG), B X1, 1 X1 or 1 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.
- Go to next step: If the test lamp illuminates
Ignition OFF, disconnect the X2 harness connector at the G13 Generator, engine running.
Test for 1 V or greater between the control circuit terminal 1 X1 and ground.
- If less than 1 V
1. Ignition OFF, disconnect the harness connectors at the K20 Engine 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 greater the 2 Ω, repair the open/high resistance in the circuit.
  - If less than 2 Ω, replace the K20 Engine Control Module.
- Go to next step: If 1 V or greater
Ignition OFF, disconnect the harness connectors at the K20 Engine Control Module, ignition ON.
Test for less than 1 V between the control circuit and ground.
- If greater than 1 V,
  Repair the short to voltage on the circuit.
- Go to next step: If 1 V or less
Test or replace the G13 Generator.