My son-in-law's Blazer is showing about 16 to 18 volts on the volt gauge. Is there anything to look for before replacing the alternator? The old battery was fried, so we put a new one in today. But the overcharging problem will cook this one in no time if it's not fixed. Can solid state regulators malfunction and cause the alternator to fully charge all the time, which is what it seems to be doing. I know the old mechanical regulators could stick and cause this, but I've ever seen an alternator with a solid state internal regulator do this.