Ford Repair: 2003 Taurus Battery Light, d2 d2, taurus 3

Question
Car: 2003 Ford Taurus 3.0L VIN: U 12 valve pushrod enginne.
66,000 miles.
Problem: Battery light comes on 8-10 seconds after cranking.
Tried so far: Replaced bad alternator, checked battery, and
cleaned battery cables. Cleaned all connections to alternator.
Tested: Belt "feels" tight enough, Voltage at battery is 14.1 to 14.2 VDC when charging.  Cables to battery have been cleaned.  175A mega-fuse connections have been cleaned.
PCM control to battery light appears to be good, not a ground but a low Z.

I don't know what the signals the PCM to set the light.  

What can I check next?  

Answer
I am not sure what your problem might be, here is the test for this condition. Apparently the PCM has something to do with the charge light, I suggest following this test sequence, in fact a code check might lead to something.



PINPOINT TEST D: THE CHARGING SYSTEM WARNING INDICATOR IS ON WITH THE ENGINE RUNNING (THE SYSTEM INCREASES VOLTAGE)
Test Step Result / Action to Take
D1 CHECK THE FAULT CODES IN THE PCM   
Connect the diagnostic tool.
Key in ON position.
Use the recorded PCM DTCs from the continuous and on-demand self-test.
Are any DTCs recorded?
Yes
REFER to PCM Diagnostic Trouble Code (DTC) Index.

No
GO to D2.
D2 CHECK THE SYSTEM FOR OVERCHARGING   
Key in OFF position.
Disconnect the diagnostic tool.
Key in START position.
With the engine running and all accessories off, measure the voltage at the battery terminals while varying the engine rpm.

Is the voltage greater than 15 volts?
Yes
GO to Pinpoint Test C.

No
GO to D3.
D3 CHECK CIRCUIT 1182 (OG/YE)   
Key in OFF position.
Disconnect: Generator C102a (4V) or C1104 (2V).
Key in ON position.
Measure the voltage between generator C102a (4V) or C1104 (2V) pin 3, circuit 1182 (OG/YE), harness side, and ground.

Is the voltage equal to battery voltage?
Yes
GO to D4.

No
REPAIR the circuit. TEST the system for normal operation.
D4 CHECK THE CHARGING SYSTEM WARNING INDICATOR OPERATION   
Key in OFF position.
Disconnect: PCM C175.
Key in ON position.
Monitor the charging system warning indicator.
Is the indicator illuminated?
Yes
REPAIR circuit 3990 (LB/RD). TEST the system for normal operation.

No
GO to D5.
D5 CHECK THE GENERATOR OUTPUT   
Key in OFF position.
Connect: PCM C175.
Connect: Generator C102a (4V) or C1104 (2V).
Verify the generator output. Refer to Component Tests, Generator On-Vehicle Test — Load Test in this section.
Is the generator OK?
Yes
GO to D6.

No
INSTALL a new generator. REFER to Section 414-02. Clear the DTCs. TEST the system for normal operation.
D6 CHECK FOR CORRECT MODULE OPERATION   
Check for:
corrosion
pushed-out pins
Connect any disconnected connectors.
Make sure all other system connectors are fully seated.
Operate the system and verify the concern is still present.
Is the concern still present?
Yes
INSTALL a new PCM. REFER to Section 303-14. CLEAR the DTCs. REPEAT the PCM self-test.

No
The system is operating correctly at this time. Concern may have been caused by a loose or corroded connector. CLEAR the DTCs. REPEAT the self-test.