Circuit/System Verification (Battery, Charging System And Starting System)

Ignition OFF, measure and record the battery voltage at the terminals. The voltage should be between 12.0-15.0 V.
- If not within the specified range, refer to Battery Inspection/Test .
Remove the drive belts. Refer to one of the following:
- Drive Belt Replacement for the 4.3L engine
- Drive Belt Replacement for the 6.6L Diesel engine
- Drive Belt Replacement - Accessory for the 4.8L or 5.3L engines
- Air Conditioning Compressor Belt Replacement for the 4.8L or 5.3L engines
Ignition Start, verify the engine does not crank normal.
- If the engine cranks normal, inspect the engine and belt drive system for mechanical binding, seized engine or seized generator.
Verify that a test lamp illuminates between the starter motor B+ terminal B X1 and ground.
- If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
Test for less than 0.5 V between the positive battery cable and terminal B X1 at the M64 starter motor as ignition is switched to start position.
- If greater than the specified value, replace the positive battery cable.
Test for less than 0.5 V between the negative battery cable and the starter motor case as ignition is switched to start position.
- If greater than the specified value, replace the negative battery cable.
If all circuits test normal, replace the starter motor.