After searching every battery/alternator thread in this forum I can't seem to find anything that matches my problem, so please help me out.

I have a 2003 v-6 escape 4x4. It's had 2 motorcraft alternators put on it in the past 18 months. After sitting for 8-12 hours, when it's started, the battery light is on and the vehicle is running on straight battery. After it starts to get warmed up the alternator will intermittently charge and after it gets warmed up or driven a mile or two the battery light will go out completely and not come on until the vehicle cools down completely again. While driving the light will flash like it has a loose wire, but I've checked the wiring extensively and can find nothing. Voltage output on the alternator is very good. BTW--the alternator doesn't have 30K miles on it and the previous 2 alternators did virtually the same thing. The battery load tests good and the alternator is always showing output by the time I can get it to be tested. Anyone have any clues??? It's almost like the "regulator" is waiting on a signal from the PCM to start working.