Voltage drain--nothing 'on'

-after set 4 days, barely cranked-alt ok, NEW bat–pulled ‘+’ cable & inserted test light between/terminal/cable–light pulses, hiccup noise under left dash (undetermined location)pulling fuse (radio cluster/underhood light) if set 2 days

The term that you are searching for is "current drain."
The test light method does not work for newer cars (those made in the last decade or two). The reason is that many electronic modules are always powered, and they need full voltage for them to be able to go into sleep mode. What you need is a current meter with at least a 10 amp range. A cheap digital multimeter will do for this.
Pull a battery cable off and connect the meter between the cable and the battery post. You’ll have to do this in some sort of way that it will stay connected by itself. When you first connect it, it may read a few amps. Don’t touch anything for 30 minutes or so, and see if the current has gone down to less than 50 mA. If so, you don’t have a drain. (You have to wait the 30 or so minutes for all the modules to go back to sleep after you woke them up by disconnecting and reconnecting the battery.

Thanks very much you have substantiated what i reckoned albeit a salvage yard mechanic stated that the 'test light insertion & pulling fuses would pinpoint my drain–& the computor goes to sleep and does NOT pull juice"–as I am from the flathead V8 '49 Ford era-but had thought the computer or relays were the cause–also the batery was original from 2002, he had tested it under starter/headlight use as 'good-you don’t need a battery–but w/cold weather enroute, I replaced…THANKS AGAIN & HAPPY HOLIDAYS–YOU’VE MADE MINE + EDUCATED ME!!!