Circuit/System Testing

Ignition OFF, measure and record the battery voltage at the C1 Battery Terminals.
Verify the measured voltage is between 12 - 15 V.
- If voltage is less than 12 V or greater than 15 V
  Refer to Battery Inspection/Test .
- Go to next step: If voltage is between 12 - 15 V
Verify that a test lamp illuminates between the M64 starter motor B+ terminal A X2 and ground.
- If the test lamp does not illuminate
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.
- Go to next step: If the test lamp illuminates
Test for less than 0.5 V between the positive battery cable and terminal A X2 at the M64 starter motor with the ignition in the START position.
- If 0.5 V or greater
  Replace the positive battery cable.
- Go to next step: If less than 0.5 V
Test for less than 0.5 V between the negative battery cable and the M64 starter motor case with the ignition in the START position.
- If 0.5 V or greater
  Replace the negative battery cable.
- Go to next step: If less than 0.5 V
Remove the drive belts. Refer to Drive Belt Replacement , for the 2.0L (LTG) or 2.5L (LCV) engines or Drive Belt Replacement for the 3.6L LGX engine.
Verify the engine cranks slowly when attempting to start the vehicle.
- If the engine cranks at normal speed
  Inspect the engine and belt drive system for mechanical binding, seized generator etc.
- Go to next step: If the engine cranks slowly
Replace the M64 starter motor.