1998 Oldsmobile Bravada car problems

There is a procedure for finding a battery draw like that.

You will need a digital ammeter and a jumper wire with clips on the ends to do this.
First rig any door switches so you can have a door open without triggering the interior lights and unplug the hood light. Remove one battery cable and attach the meter in series between the battery cable and battery post. Take the jumper wire and also attach it the same way. Leave the jumper wire on for at least 10 minutes to expire all the automatic timers. Now remove the jumper wire and read the meter. Anything over 50ma is too much draw. The way you locate this is to start removing fuses one at a time until the meter drops to normal level. This will be the circuit with something staying on. Determine what components are part of that circuit and check them individually until the problem is isolated.

I put multimeter between negative posts and negative cable, and I have 12 and 1/2 volts. Pulled each fuse one at a time from under the hood and under the dash including relays and made no difference battery is brand new and goes dead is as soon as you hook up both the negative and the positive post within one minute you have time to get dash lights but do not have enough time to even try and start it but it will not turn over unless you have it unless I have 200 cranking amp charger hooked up then it will turn over but will not start.

Can you place your hand on the alternator to see if it is warm? If so this is your problem. An alternator can short out internally causing the issue you have described.