I don't come here often but this is a necessary read:

Starting about two years ago, most of the GEN 1 cars I've bought have had low voltage to the battery and in every case it was the B cable, the long cable that runs under everything and takes a good hour to hour and a half to replace.
The cable corroded and it loses the ability to carry 13.5 volts to the battery and eventually you wind up with a dead battery.
Many are fooled thinking they need an alternator when all they need a replacement cable.
Do yourselves all a favor, if your cables are original you most likely need new ones or at least the one B cable.
Do a battery load test, this is the easiest way to find out.

What I didn't know is there was a TNN that apparently came out in about 2003-2004 that specifically addressed this problem.