I have a 2000 blazer 4x4 LT. The push button switch lit up in all modes 2 hi,4hi,4 lo, and auto then went off. The module was clicking and shifting on its own. It was killing my battery by shifting on its own and staying on some how with the blazer turned off. I found corrosion on two pin with 4 pin connector. It was the orange wire and one of the black wires. On the 32 pin connector I found 2 pins that had some corrosion on then, but cleaned then two and applied die electric grease to then to prevent moisture. Reconnected everything back the lights came on and the transfer case control module started clicking again, but then every thing stopped. All lights went off on the 4x4 switch and no sound from the module. I can't find the fuse or any diagrams for this model. The blazer will run, but not fast it can't decide which gear to be in lol. Is it possible to put it in 2 wheel drive manually for now???????? and does anyone know where I can get a wire diagram on the transfer case control module with 2 plugins that has a 32 pin plugin and a 4 pin plugin, with red,2blacks, and one orange wire. I need help I have to get this blazer running again.

 

Hey, I have the same exact problem with my 2000 blazer. Did you ever find the problem for yours?

 

Heres how to put it in 2 wheel drive if you cant control it electronically, but its not easy....not that hard either though...
You need to remove the front driveshaft (take out 4 bolts on front U-Joint) and then remove the transfer case shift motor from the transfer case. There will be a stub sticking out of the case, you need to turn this to shift the t-case, i just read in another post on the forum about a ghetto electric to manual conversion that all the way clockwise is 2WD. BLOCK THE WHEELS when doing this, you can actually shift the t-case into neutral and the vehicle will roll so be careful!! Now once you get that turned to 2wd you will be able to turn the front output shaft on the t-case, thats how you will know youre back in 2hi, the shift motor will not fit back on now because it will be clocked wrong to the stub, you can leave it off until you figure out whats wrong with the module. You may want to pack that connector with grease and tape it up so the pins dont get corroded.

As far the electrical issues, it could be a bad ground causing all of these problems but its too hard to diagnose over the internet, it really needs to be hands on by someone with experience in electrical diagnostics. If its still draining the battery then a good start would be to do a parasitic draw test, google it or try youtube, its the same for any vehicle, connect a meter between the negative battery cable and negative battery terminal and set it to amps, note the amp reading, if its above 50 milliamps you need to start pulling fuses one by one and leave them out when you pull them (take a good picture before you start pulling), when the amps drop you have found your problem circuit and will need to find a wiring diagram related to that fuse, then you need to unplug every component on that circuit until you find the bad part. Also before pulling all of your fuses check them with a test light with key on to make sure theyre good.
I hope this points you in the right direction.
Good luck!