Hey Everyone! New to the forum here.

Back in April i made the same mistake that I keep making; I Purchase cheap project cars on craigslist thinking that i'm skilled enough to make something great out of them.
My 3rd addition to my garage is 2002 Suburban Z71
Mechanically it's fine, Engine runs great, transmission shifts great, transfer case is engaging the 4 different drive modes. It steers, it stops, and it still has great power for an 18 year old truck.

I had been daily driving it for about 2 months with no issues. About 2 weeks ago, I got into the truck to go to work, and the battery was completely dead. And since it was a new battery, I figured maybe i left the dome lights on from the night before.
I hooked up my jumper cables, and before i could even put my key in the ignition, the Blower motor was on BLAST, keep in mind the fan control was off, key was in my pocket.

So I thought that was weird, Started checking fuses, pulled all the fuses i could find to turn off the blower motor, to no avail (Probably never found the right one) but after a few minutes, it turned off on its own, and i haven't had an issue since. Drove the car for a few days, then it happened again.

​​​​​​This time, I walked up to the truck and i heard the door chime through the closed window, I walked around the car to see if any of the doors were cracked, they were all closed completely. So i opened the door thinking maybe the headlights were left on, also no. the headlight switch was in the off position. Put the key in the ignition, voltmeter shows battery around 9 volts. Jumped the car, drove it around for a few days no issues.

THEN! someone broke my damn window, didn't even take anything, just wanted to be a jerk, Killed my battery leaving the dome lights on while searching the vehicle. Jumped it yet again, and now this morning, Went out to take the car to get the window replaced, and the door chime was the first thing i heard walking out of my house. Battery is dead yet again, and i'm getting tired of it.

Did some research and I'm seeing that it can be a few things, maybe the ignition switch, maybe the door sensors that tell the computer when the door is ajar, I don't want to just throw money at this car, it needs a few other things, but this absolutely takes priority as i'm not a big fan of being stranded. So what do you guys think?

 

I had an ignition switch causing the same issue.

 

I’ve had similar issues with 07 Tahoe for 9 years. I finally found an electrical specialty shop that believes they found and fixed the issue. Keep in mind, over the years, no one found a problem but just suggested I throw money at it (new BCM, new alternator, new batteries). Here’s what they found back in April and I’ve been good since:
1) door latch sensor wasn’t accurately telling the computer to turn off.
2) Short in the lumbar function of power seat.

They “fixed” the latch and disconnected the lumbar function in power seat. $165 for an out and a half.

Good luck!

 

I'd change the blower relay, they can stick on erratically.