Question about 2003 Ford Windstar
It should notgo over 14 1/2 volts.
Get free DTC codes scan from Autozone. I think you will get DTC code 1246 - System Voltage Malfuction.
The I (indicator) (BAT light) wire activates alternator field circuit.
The heavy B wire circuit sends current to the battery for charing and to run the car.
The S circuit helps control the amount of charge. I suspect yours is not controlling. This car has the PCM (engine computer) help control the output and turn the BAT light on when under or over charging.
SECTION 414-00: Charging System - General Information 2003 Windstar Workshop Manual
DESCRIPTION AND OPERATION Charging System This vehicle is equipped with a powertrain control module (PCM)-controlled "smart charge" charging system. The PCM-controlled charging system is a system whereby the PCM determines the optimal voltage setpoint for the charging system and communicates this information to the voltage regulator. The PCM-controlled charging system is unique in that it has two uni-directional communication lines between the PCM and the generator/regulator. Both of these communication lines are pulse-width modulated. The GEN COM line communicates the desired setpoint from the PCM to the voltage regulator and the GEN MON line communicates the alternator load condition to the PCM. The third pin on the voltage regulator, the A circuit pin, is a dedicated battery voltage sense line.
Generator The generator (10300) on this vehicle is monitored and controlled by the powertrain control module (PCM). The PCM monitors the voltage regulator and sends a duty cycle command back to the voltage regulator to regulate the amount of field current supplied to the generator. The generator has an internal voltage regulator. The generator and voltage regulator are installed as an assembly.
I'll send wiring diagram tomorrow.
Posted on May 20, 2011
I am having the same problem since i replaced the alternator 2 years ago, the battery light has always been on but everything seens ok even wen i went to the mechanic today i was working in the car i didnt touch any elctrical that could affect the alternator and when i was driving my the needles and ODO in the cluster get to the top, like whem you first turn the key to ACC, I have discover that this happens exactly when the alternator sends above 15 volts to the B+ terminal, i will check continuity in the cables tomorrow but it seens like the PCM that controls the alternator is sending a high field current that could be the reason why the voltage is almost 18V
Posted on May 06, 2013
Computer controls voltage output of alternator
Posted on May 20, 2011
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Posted on Jan 02, 2017
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