Squeaky Alternator

91 deville has a regular squeak coming from the one of the accessories on the serpentine belt. I replaced the tensioner pulley and the water pump is only a couple of years old with very few miles on it. I've tried the stephoscope routine but could not come to a conclusion. Then I removed the belt and spun each and heard a squeak coming from the alternator. Everything else moves fine excpet there is a very slight play in the lower idler pulley. The water pump doesn't freewheel but it isn't hard to turn either. (Pretty sure it shouldn't freewheel with coolant behind it. Correct me if I'm wrong.)


So I'm thinking the alternator is the culprit. However, my battery charges and the pulley on the alternator spins just fine aside from the squeak. Should I pull it and take a look? Any advice is helpful.