So first and foremost... If the voltage gauge dips down to 12.7, that is too low right?
So the other day I was driving at night and I could tell the instrument cluster was occasionally dimming. I flipped over to display battery voltage, and my volts were consistantly in the 13s (which may be low but, high 13s is normal for my car). Then, this past weekend, I was just driving around and when I would stop at red lights the voltage would dip down into the 12s. The volts did not seem to go up and down parallel to revving the engine.
Either way, I took the battery and the altenator to the local auto supply store for testing and they both tested great. The altenator should be fine it was replaced 3 years ago (< 15K miles). I know the voltage regulator in an 88 Corvette is in the altenator, and again it tested fine. The only idea I have left is to put it all back together and make sure the drive belt is tight.
Any ideas would be very helpful. Thanks in advance.