Alternator voltage dips

When driving my car normally and I am slowing down to a stop, either while I am clutching to downshift or when I stop, my lights dim and my voltage drops to just under 13v. It just does it at random times but never while the gas pedal is depressed. It won't do it while the car is just idling either. Do you think my belt is slipping, alternator or some other part is failing? I can hear no noise from the belt at all and the car has 37k on it. Thanks in advance for any help.

hmm..... id get a battery starting and charing test done at the dealership, one hour checkout fee, test your battery, starter, and alternator in a single test, for circuit failures, charging problems, bad cells, yadda yadda, thats where i would start.

Ok thanks 89, guess I gotta shell out some cash to them greedy dealership techs <grin>

lmao!!!! yup yup, somewhere near by a tech is rubbing his hands together with an evil grin haha