Ford 2003 Mustang Workshop Manual page 3349

Connector C102a End View
A Circuit 36 (YE/WH)
I Circuit 904 (LG/RD)
Functionality
With the ignition switch in the RUN position, voltage is applied through the warning indicator I circuit
904 (LG/RD) to the voltage regulator. This turns the regulator on, allowing current to flow from battery
sense A circuit 36 (YE/WH) to the generator field coil. When the engine is started, the generator
begins to generate alternating current (AC) which is internally converted to direct current (DC). This
current is then supplied to the vehicle's electrical system through the output (B+) terminal of the
generator.
Once the generator begins generating current, a voltage signal is taken from the generator stator and
fed back to the regulator internally. This voltage feedback signal (typically half the battery voltage) is
used to turn off the warning indicator.
With the system functioning normally, the generator output current is determined by the voltage of the
A circuit. The A circuit voltage is compared to a set voltage internal to the regulator, and the regulator
controls the generator field current to maintain the correct generator output.
The set voltage will vary with temperature and is typically higher in cold temperatures and lower in
warm temperatures. This allows for better battery recharge in the winter and reduces the chance of
overcharging in the summer.
Battery Positive Output Circuit 38 (B+) (BK/OG)
The generator output is supplied through the battery positive output (B+) terminal on the back of the
generator to the battery and electrical system.
I Circuit 904 (LG/RD)
The I (ignition) circuit is used to turn on the voltage regulator. This circuit is powered up with the
ignition key in the run position. This circuit is also used to turn the charging system warning indicator
on if there is a fault in the charging system operation.
A Circuit 36 (YE/WH)
The A circuit or battery sense circuit is used to sense battery voltage. This voltage is used by the
regulator to determine generator output. This circuit is used to supply current to the generator field
(rotor). The amount of current supplied to the rotor will determine generator output.
Inspection and Verification
WARNING: Batteries contain sulfuric acid. Avoid contact with skin, eyes, or clothing.
Also, shield your eyes when working near batteries to protect against possible splashing of the
acid solution. In case of acid contact with skin or eyes, flush immediately with water for a
minimum of 15 minutes and get prompt medical attention. If acid is swallowed, call a physician
immediately.
WARNING: Batteries normally produce explosive gases which can cause personal injury.
Therefore, do not allow flames, sparks or lighted substances to come near the battery. When
charging or working near a battery, always shield your face and protect your eyes. Always