RE: 2000 S-10 Blazer wiring problems
AllDataDIY.com is a good source for wiring diagrams, it just depends on how difficult or easy it is to find them using their layout.
The FSM will have everything that you require, but is $$$ and again, it may not be in the most logical place. I don't think I have spent over $80 on any of the FSMs that I have purchased for my vehicles (eBay), but don't see anything reasonably priced for a 2000 S/T...
As far as complete wiring diagrams go for a '00, I can get you some of those parts through the AllDataDIY account I still hold for my 2000 Bravada (AllData doesn't distinguish between Bravada/Jimmy/Blazer), but you have to be specific as to the circuits you are interested in.
Basically, to solve your problem, you need to work through the system to figure out where your draw is originating from. Start at the battery with the DMM in amps (or mA) mode. Remove the negative terminal, connect one lead to the battery negative and the other to the negative cable. Start removing fuses until you see a drop in the amperage. Note the drop and move on until you see zero amp draw. Once you have a good feeling of the offending circuits, I can try to get you some diagrams.
Or you could pick up an AllDataDIY.com account for yourself if you want to browse around. Not sure what they are for the initial subscription, but I know I just put on another vehicle for my aunt & uncles Stratus this past weekend for $10/yr ($30/5yrs if I wanted to go that route).