GM/Detroit 6.5L – CRANKING CIRCUIT

BATTERY
Determine the condition of the battery. Refer to SEC­TION 6D1 for battery diagnosis and testing.

WIRING
Check the 10-amp CRANK fuse. Inspect the system for open circuits, loose terminals inside connectors, cor­rosion, and damage. Verify that no wires are pierced by screws and no harnesses are missing insulation by rub­bing on components. Inspect all connections to the starter motor, solenoid, ignition (or engine control) switch, and battery, including all ground connections. Clean and tighten all connections as required.

SOLENOID AND CONTROL SWITCHES
Inspect all switches to determine their condition. Vehicles equipped with manual transmissions have a neutral start switch attached to the clutch pedal that closes when the pedal is depressed. Vehicles with auto­ matic transmissions have a mechanical interlock in the steering column that does not allow the ignition switch to turn to START unless the transmission is in PARK or NEUTRAL.