Unhooked Battery, now it won't start- Please help! *SOLVED*

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Wes
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and just for s@hits& giggles, start checking each fuse, only takes a couple minutes on the top of each fuse is 2 metal tabs, put your meter on continuity and probe each fuse
 
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Scrapman

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that is a discharged battery
It was higher when I started jacking with it at about Noon today. I have checked all the fuses under hood and in the cab, and even charged the battery with my truck. I have had Zero battery problems until I unhooked it today.

it is like one of the computers (BCM Maybe) turned off and isn't coming back on.

I need to find a shop manual and electrical diagram and dig into them. I have only owned this Tahoe for about a year, but it was well taken care of. The engine is cleaner that my wife's one year old car.
 

wsteele

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It was higher when I started jacking with it at about Noon today. I have checked all the fuses under hood and in the cab, and even charged the battery with my truck. I have had Zero battery problems until I unhooked it today.

it is like one of the computers (BCM Maybe) turned off and isn't coming back on.

I need to find a shop manual and electrical diagram and dig into them. I have only owned this Tahoe for about a year, but it was well taken care of. The engine is cleaner that my wife's one year old car.
There are a ton of YouTube videos on ways guys got their Theft Deterrent system straightened out. The ones where guys stand on one foot holding their breathe I probably would skip.

One constant in most I scanned was the battery needs to be kept charged, the tow guys all use jumpers during their procedures. I would probably get and keep that battery charged up (should read 12.7+ after a charge). The charge state should be taken with the battery disconnected from the truck or quite a while after shutdown, lots of parasitic drag as things spool down that will look like a low charge state.

The 30 minute key relearn procedure is probably worth a shot.
 
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Scrapman

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There are a ton of YouTube videos on ways guys got there Theft Deterrent system straightened out. The ones where guys stand on one foot holding their breathe I probably would skip.

One constant in most I scanned was the battery needs to be kept charged, the tow guys all use jumpers during their procedures. I would probably get and keep that battery charged up (should read 12.7+ after a charge). The charge state should be taken with the battery disconnected from the truck or quite a while after shutdown, lots of parasitic drag as things spool down that will look like a low charge state.

The 30 minute key relearn procedure is probably worth a shot.
My security light is Not on. Your saying do the key relearn procedure even though the security light is Not on?
 
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Scrapman

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Don’t sound so incredulous you’ve tried everything else….
I wasn't trying to, but the key relearn procedure uses the security light going off to relearn the keys. How am I supposed to do it if the light isn't on?
 

wsteele

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My security light is Not on. Your saying do the key relearn procedure even though the security light is Not on?
I understand your security light is not on. You told me that before.

What I am suggesting is something in your BCM/PCM is not happy and given you were screwing with components that talk to the BCM and interact with the Theft Deterrent system, perhaps a procedure that resets programming in those modules may clear the state you may have induced.

As I posted before, there are tons of YouTube videos that document n number of ways to reset components in this logic train. One likely will work for you.

good luck.
 
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wsteele

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I wasn't trying to, but the key relearn procedure uses the security light going off to relearn the keys. How am I supposed to do it if the light isn't on?
So make it 13 minutes between off/on/start cycles. Or maybe try in succession the procedures documented in the first 19 YouTube videos that address similar problems.

Without a high end two way scan tool, it is going to be a kind of blind man’s bluff thing.

It is possible it isn’t even a theft deterrent problem. It could be a fried liftgate control module, BCM, PCM, crank relay, etc. etc. etc.
 

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