1991 Buick Park Avenue • 89,000 miles

The car came to me with a charging system concern. Charging voltage would drop gradually as loads were applied until the charge light came on. Alternator, battery and even the instrument cluster were changed in an attempt to repair this problem. After extensive reaserch and checking, I am noticing a rythmic/signal type voltage on fuses #6, 7, 8 on the driver's side fuse block, and the same on #5, 6, 7, 8 on the passenger side fuse block. This is all with the alternator connector unplugged. I need serious answers only. The pink/black wire when measured with my power probe has the necessary voltage when KOEO. When Vehicle is started, it pulses fast, then for a split second drops to 0, then back to pulsing fast. It seems like it's picking up a signal feed from some component or sensor. I need help!
MX Mitchy 175
November 4, 2012.

First of all, as load increases and amperage out increases in the alt, voltage will drop. This is normal.

Does the battery go dead? Is the light on?

I would like to start from there. Use your amp probe and tell me the amperage under load