Cadillac Repair: electrical problem, cadillac man, turn signals

Question
Hey Ben, I know you are listed as a cadillac man but  I was hoping maybe you could be of assistance on my Buick. Its a 1994 Roadmaster (lt1). Recently I noticed when idling at a light the dash lights and radio, and climate control lights would flicker a bit. I went and had the alternator tested. It started putting out like 16 amps than would gradually descend and bottom out at around 10 to 11 amps. I went and replaced the alternator and it seems to be doing the same thing again. You will be sitting at a light with the fan setting on high and you can hear the fan slowing down on idle. Upon acceleration it seems to increase again. Also the turn signals seem to be operating slower than normal. The battery was tested and was said to be O.K. Any insight?   Thank You in advance

Answer
My guess is there is a bad connection at the battery, specifically the ground on the engine block, this is the most likely cause, As long as your battery is being charged the alternator is good, but i would say there is a bad ground on the engine block.