charging system woes

:runaround: my '93 302 ho is having issues. Past couple of days going to work it the discharge light started coming on and off. First day on for a minute or two and off for a while, then on again. Next day it would come on for longer periods. Today on the way home from work it came on and stayed on for 45 minutes. I have a brand new duralast and I drove home with nothing on but was still surprised I made it home. I couldn't find my multimeter to verify, but I figured the a the diode was getting hot so I replaced the alternator (V-regulator attached to back) this evening. No change. I finally found my meter and even though the discharge light is on and the voltmeter reads around 10 V, the meter read 13.5 (fluctuating some to 12.5-ish) at the battery terminals when my wife held the tach around 2k. At idle it wasn't much over 12V. So I know there isn't a whole lot to the charging system but I can't for the life of me find my Haynes diagrams. I am thinking high resistance open somewhere but haven't found any hot spots in the wire. Then theres the chance of a bad ground, but without the diagrams I really don't know where to start. Any pointers in the right direction or things I can rule out would be greatly appreciated. I have a degree in electronics and used to work on aircraft but have lost too many brain cells working for the phone company :screwy: and am too damn tired this week to start blind on my only day off before the start of what is going to be another long work week. I haven't even had time to put the rack and pinion assy sitting in my living room on my stang and that should probably be done before I kiss a tree. Any help would be appreciated.