New problem they just keep coming.uhhh

My 1998 S-10 2.2 Liter has starting draining the battery dead overnight.The battery and Alt were checked today and they were fine no problems at all.It drains every ounce of juice out of the battery even the small light under the hood or the interior light won't come on the next morning.My volt meter is jumping around from 13.5 to 16.5 but the charging system checked out ok today any ideas of what I could check i'm clueless on this one...

The only real way to find the problem is to disconect the battery ground wire. Pull 1 fuse then touch the ground back up to the battery post. If it sparks put that fuse back in and try again , and again until the sparking stops.

Once you find the fuse that is causing the problem put it back in disconect 1 item from the circuit, and do the same process over again until you find the circuit causing the problem.

Once you find the very circuit it's just a matter of tracing the wire down looking for any possible problem.

Good luck, and don't get frusterated. That's just about the worst problem in auto electric

Another option is to hook up an ammeter in series between the negative post of your battery and the negative battery cable. Take note of the current draw. Pull fuses one at a time until you wind the circuit the causes the current draw to decrease (you should be at less than 20mA). Once you find the circuit, begin isolating the items on that circuit that are causing the draw. You may have a wire shorting to ground. This is one of those things that could take 5 minutes or 5 weeks to figure out. Good luck!