1212 Golf Road

Waukegan, Illinois

(847) 623-9609

Effective operation of a vehicle's electrical system depends on a good battery, a charging system that can keep the battery charged, and a starting system that can properly utilize the battery power.

Just a note:  Our newest testing equipment is the state-of-the-art Midtronics battery tester.  Nothing gets by this tester, including internal corrosion in the battery cables that can't be seen from the outside!   

The Charging System

The charging system keeps the battery charged and supplies the electrical needs of various units during engine operation.  All modern vehicles use a charging system that contains an alternator and a voltage regulator.  If both of these components are doing their jobs, their output amperage and voltage will be within specifications when tested. 

If the charge indicator light is on or flickers when the engine is running, the vehicle is slow cranking to start or the headlights are dim, these are all indications the system is undercharging.

The alternator generates direct current for recharging the battery and for powering vehicle electrical loads. It consists of a spinning set of electrical windings called a rotor, a stationary set of windings called a stator, a rectifier assembly, a set of brushes to maintain electrical contact with the rotor, and a pulley. All of these parts except the pulley are contained in an aluminum housing.

Many late-model alternators use sealed bearings which eliminates the need for periodic lubrication.  Dry or worn bearings can cause roaring or squealing noises.  In many cases, replacement parts are not available and the entire unit must be replaced if defective. 

The voltage regulator manages the alternator’s output according to vehicle operating conditions. The voltage regulator is an electronic device that regulates alternator output according to the battery’s state of charge and accessory loads. Today’s compact electronic voltage regulators may be housed inside the alternator or the voltage regulator function may be handled by the vehicle’s powertrain control module (PCM).

The Starting System

The starting system consists of the battery, starter motor, starter solenoid, relay, ignition switch, neutral-safety switch and related wiring.  Often, determining which part is at fault when the engine will not turn over is more difficult than replacing the defective parts. 

Many complaints of poor starter performance are traced to a discharged or defective battery.  Likewise, corroded and dirty battery terminals can be at fault.  The battery must have enough capacity to turn the starter.

The starter cranks the engine when the ignition switch is turned to the start position. The starter consists of an electric motor that powers a starter drive-a special pinion gear designed to engage with the ring gear of the flywheel or torque converter. The starter is usually mounted to the rear of the engine or the front of the transmission housing.

The starter solenoid supplies the high current needed to run the starter motor and also provides the force needed to engage the starter.  Starter solenoids can either be mounted on or made as part of the starter.  Although similar to the starter relay, the solenoid converts electrical energy into linear motion. The solenoid contains a set of windings that, when energized, cause movement of the solenoid’s plunger, which then engages the starter.

The starter relay is high-current switch used in the starting circuit of some cars. The starter relay makes and breaks the connection to the starter, based off a signal from the ignition switch.  A starter relay is usually mounted to the firewall area underneath the hood. 

The ignition switch allows the driver to start and stop ignition by opening and closing the circuit between the battery and the other ignition components. The key switch usually has four positions: OFF, ACCESSORY, ON, and START.

All vehicles with automatic transmissions have a safety lockout switch which is usually called the neutral safety switch.  This switch will not allow the ignition switch to energize the starter solenoid unless the transmission is in neutral or park.  Manual transmissions have a safety switch installed on the clutch linkage which prevents starting unless the clutch pedal is depressed.