need a little help... thank you

[Terrence allen]

I have a 2000 Tahoe z71
every two days battery goes dead had the battery and alt checked tested all good no problems there and I checked all the interior lights and none are on so I put a test light in between the the negative terminal and negative battery post and it lights up so I pulled all the fuses and relays from under the hood the box by the master cylinder even pulled all the fuses and relays from the box inside on the left side dash panel and the light still stayed on but when I pull the big 50 amp fuse out the one says "Battery" the the test light goes out ..now I lost on what to do next I need to solve this battery drain problem ASAP if anyone has had this before I need your help id appreciate it... thank you

[Terrence allen]

instead of using a test light to find this battery drain a few hours ago I went to autozone and bought a digital multi-tester and tested the alternator and the battery both running and non running and they both tested good so now I put the tested in between the negative post and cable tester says 1.15 and slowly drops to 0.01 flickering to 0.00 back in forth? I then fixed the door so the Lite won't come on so it won't interfere with the testing and give the wrong reading so I started pulling fuses and relays from the box that's under the hood I pulled one by one no change then I pulled a big red 50 amp fuse marked "Battery" the tester goes to 0.00 and stays there so I left the battery hooked up then pulled that fuse marked battery no more drainage can anybody tell me what all this 50 amp red fuse supply power too? if I figure that out I'll be able to fix the drainage problem Id appreciate your help the truck is a 2000 Tahoe z71 with a 5.7

[Blue Bowtie]

You'll need a wiring diagram to begin tracing the loads in the circuit. If your meter has a current scale (at least 10 A) connect that and determine the actual current draw in standby. A few hundred milliamps is not abnormal for the RAP, radio, BCM, PCM, and other parasitic loads.

[j cAT]

the battery drain current should be below 100MA .. most it will be 50MA or less.. possible the BCM is always on .. some have had this because the BCM kept the radio on / amplifier etc.. then the glove box light or under hood lamp . fuses in the vehicle and under hood pull one at a time with meter setup ..digital meters are harder to show this compared to an analog meter that has a needle indicator .. you say .01 amps ??? or ??? .. clamp type meters do work better to get the most accurate current reading . other causes alternator disconnect the big wire ,, then any aftermarket electrical installed ...these can turn on unexpectedly... drain battery ....

[Terrence allen]

I didn't have the clamp type all I had was a digital multi tester I did the test and the meter reads 0.01 kinda jumps back and forth to 0.00 I know there is a drainage somewhere cause when I put the negative cable on the post it sparks a quick pop then it cool think after that It won't spark again unless you unhook it then hook it back up I've pulled every fuse and relay and no change still says 0.01 but there is one big 50 amp fuse marked "Battery " if you pull it out the meter goes to 0.00 and the drainage stops.. can somebody tell me what that 50 amp fuse runs I have a 2000 Tahoe z71 5.7

[777stickman]

The 50a fuse #7 in the Old Body Style (looks like a '95) (no BCM) powers 3 circuits. I'm assuming you have the OBS due to the 5.7 motor.

1. Stop/Haz 20a fuse #1
2. T-Case 20a fuse #2
3. PWR ACCY Circuit Breaker also in the I/P fuse block. This C/B powers the Keyless Entry Module, the Power Door Locks and the Power seats.

Hope this helps.

[Terrence allen]

yea it a 5.7 vortex 350 the fuse box is next to the master cylinder.... so are you saying the big red 50 amp fuse marked battery Powers the fuses that runs 3 things you listed or am I reading into it all wrong idk

[Tech II]

That 50 A fuse goes to the ignition switch and then feeds 9 fuses, and some of those fuses feed more than one circuit....

You will get a big spark when you go to reconnect the bat cable, because you are completing circuits through "awakened" modules......there will be an initial high current flow, but over the course of 10 minutes, current should drop to about 30-25 ma or 0.030-0.025 Amps......

[Terrence allen]

the truck will star up and run even without that 50 am fuse

[rhandwor]

Try disconnecting the alternator and check for a drain. Sometimes a relay will stick and cause a drain.

[Tech II]

It would help to get a true reading of this draw......

Make sure everything is off, key out of ignition, underhood light not on.....

Remove the BAT ground cable from battery.......take a jumper, and jumper the neg bat terminal(threading a bolt into the battery makes this easier to attach) to the neg battery cable......let sit for about 10 minutes......this gives all the modules time to go to sleep.....now hook up your amp meter in parallel with that jumper....now remove the jumper leaving the amp meter connected.....now you have a true reading......what is the draw? It is suppose to be 0.025 to 0.035 Amps......is it higher? If it isn't, the problem is not a draw.....