Caprice V8-265 4.3L VIN W MFI (1995)
Volt Meter Gauge: Initial Inspection and Diagnostic Overview
Circuit Operation - Starter
Battery voltage is applied to the Ignition Switch at all times through Maxifuse 11. When the Ignition Switch is turned to "START" battery voltage is
applied through the closed contacts of the Ignition Switch, (through the contacts of the Theft Deterrent Relay. This relay is controlled by the Theft
Deterrent Module, (NON SEO)). Then it goes to the Starter Solenoid at terminal "S". When battery voltage is applied to terminal "S" of the Starter
Solenoid Switch, the Hold-In Coil and Pull-In Coil of the Starter Solenoid switch are energized with the Pull-In Coil grounded through the Starter Motor.
The coils, when energized, work together to pull in and hold the Plunger of the Starter Solenoid switch. As the Plunger is pulled in, it closes the Starter
Solenoid Switch contacts and causes the Shift Lever to rotate, engaging the Drive Assembly to the Flywheel. With battery voltage applied directly to the
Starter Motor through the closed Solenoid Contacts, the Starter Motor begins to rotate the Drive Assembly as the Drive Assembly comes in contact with
the Flywheel. The Pull-In Coil is de-energized by having battery voltage at both ends of the coil. The Starter Motor continues to rotate to crank the
Engine through the Drive Assembly-Flywheel gear combination.
Battery voltage is removed from the Starter Solenoid terminal "S" when the Ignition Switch is released from the "START" position. The Hold-In Coil is
de-energized and the return spring in the Starter Solenoid Switch causes the Plunger to disengage the Drive Assembly from the Flywheel. As the Plunger
returns, the Plunger opens the Solenoid Contacts removing battery voltage from the Starter Motor.
Circuit Operation - Charging
The Generator provides voltage to operate the vehicle's electrical system and charge the Battery. The Regulator supplies current to the field coil of the
Rotor. When current flows through the field coil, a magnetic field is created. This field rotates as the Rotor is driven by the Engine, creating an AC
voltage and current in the Stator windings. This AC signal is converted to DC by the rectifier bridge and available to the vehicle's electrical system at the
"BAT" terminal.
The Generator must supply sufficient current to all vehicle electrical loads especially for charging the vehicle's Battery. Since the Rotor speed varies with
Engine speed, the Generator must also maintain the output voltage at a constant value. The Generator's Regulator switches current to the field coil of the
Rotor on or off controlling the output voltage of the Generator. When the Ignition Switch is turned to "RUN," battery voltage is supplied from U/Hood
Fuse #8 to the Generator at terminal "F", turning on the Regulator. If for any reason terminal "F" did not supply any current to the connection inside the
Generator, the Regulator could still turn on because CKT 25 would function as a backup source of "TURN ON" current.
The Regulator switches on the field current by connecting the field coil of the Rotor to battery voltage available at the "BAT" terminal.
The field current creates a weak magnetic field in the field coil when the Engine is being started. The Regulator senses Generator rotation by detecting an
AC voltage at the Stator through an internal wire. Once the Engine is running, the Regulator can monitor the internal AC voltage and DC output at the "
BAT" terminal. The Regulator will then vary the current in the field coil of the Rotor as needed, to provide a constant output voltage and adequate
current to the electrical system of the vehicle.
Circuit Operation - Check Gage Indicator
Battery voltage is applied to the Instrument Cluster through I/P Fuse #11 whenever the Ignition Switch is in "RUN," or "START." A ground is provided
at the Generator "L" terminal when the Regulator senses a high or low voltage condition or when the Rotor stops turning.
Troubleshooting Hints - Charging System
PERFORM BEFORE BEGINNING SYSTEM DIAGNOSIS:
1. Visually inspect the hydrometer (built into Battery).
^
Green dot - Battery is charged.
^
Dark dot - Charge and load test Battery. If Battery passes load test, refer to System Diagnosis. See: Starting and Charging/Testing and
Inspection/Initial Inspection and Diagnostic Overview/Preliminary Information - Starting System
^
Clear or light yellow dot - Battery electrolyte is low. Replace Battery.
2. Check U/Hood Fuse #8 and I/P Fuse #11. Check Maxifuse 11.
3. Check that the Generator Connector and Generator "BAT" terminal are both clean and tight.
4. Check that the Battery connections are clean and tight.
5. Check Generator belt.
^
Check for a broken (or partially broken) wire inside of the insulation which could cause system failure but prove "GOOD" in a continuity/voltage
check (refer to "General Troubleshooting Procedures,"). See: Diagrams/Diagnostic Aids
^
Check for proper installation of aftermarket electronic equipment which may affect the integrity of other systems (refer to "General
Troubleshooting Procedures,").
^
Refer to System Diagnosis.
Troubleshooting Hints - Starter
PERFORM BEFORE BEGINNING SYSTEM DIAGNOSIS:
1. Visually inspect the hydrometer (built into Battery).
^
Green dot - Battery is charged.
^
Dark dot - Charge and load test Battery.If Battery passes load test, refer to System Diagnosis. See: Starting and Charging/Testing and
Inspection/Initial Inspection and Diagnostic Overview/Preliminary Information - Starting System
