Last month a lady walks into a shop I was in and said her 04 blazer (103k miles) won't go into 4wd and she needs it working to sell. I said how much? $5 grand. Mechanic puts a new battery in it and says the current and voltage were not strong enough to engage the 4x4 so that fixed it. Fresh oil and a thermostat to take care of a engine lights. She paid $350. It looked well maintained and clean so I said "What do yo really want for it?" She said $2500. She said the title was with her and we settled on $2000. That's how I wound up with my Blazer so I think your on track with grounds and possible voltage. Try it with a jump or charger on it. The other thing is my 3 button only went into 4wd when the car was is in neutral. If I left it in drive it just blinked. Some manual T-cases on other rigs get a little bound up you need to bump it in reverse and then neutral to get them to shift. That just loosens up all of the gear bind so the actuator or lever can work. On my E350 van with swapped in F350 T case (looks the same only bigger) it was having a hard time engaging all the way into 2 LO. It would grind or pop out of gear. I swapped the fluid and added a cup of Lucas oil stabilizer (that think stuff) and it shifts perfect now. I put about 2/3 cup in the Blazer with fresh fluid for good measure. It will shift in drive now but it clunks so I don't do it.

Ok After further inspection .. When I push 4 hi or low those lights blink but at the same time the 2 hi light is staying on solid as well .. The 4 hi / lo lights stop blinking and then it returns to 2 hi only solid. I hear the TCCM clicking and when the lights stop blinking I hear the encoder (sounds like returning to 2 hi) .. I jacked the front right wheel up had my son push the 4 hi button and the front wheel locked in .. but the switch on the dash did the same thing showing 2 hi . So up until I pulled the 4x4 fuse it was stuck in 4 wheel but showing 2 .. I'm more lost now then I was before !

Sounds like you need to read the codes for the 4x4 problem. Service 4x4 light is still on, right?

Yes light still on .. How do I get the codes .. I've read something about jumping pin 13 to ground .. Is there a different way or do you know what pin is ground ?

Grounding the pin only works on the 3 button system, 4 button system has to be read by a capable scanner.

I am picking up a transfer case with encoder motor out of 2000 blazer tomorrow for $35.The guy just wants it gone .. (A spare transfer case is never a bad thing) Now the question is ..if that blazer was a 3 button and mines a 4 will the encoder work ?

No , totally diferent ....unfortunatly .

I don't know if it was a 3 button or not , just curious.. hopefully it was a 4 but I have a 2001 that has 3 button ( That's why I said earlier that a spare transfer case is never a bad thing ) but on that one the 4x4 works great .

Another 4x4 question
 

Ok I'm new to the site but been doing a lot of reading on this subject ok so my 4wd work but it goes into 4wd as soon as i start the vehicle up the only way I can stop it from doing that is I blocked off the vacuum line running to the thing under the battery any idea what might cause this or what I might be able to do to fix this and if I put this post in the wrong place please let me know and I'll move it:icon_rally:

You are very welcome to post and ask for help by starting your own thread. Give it a good descriptive title and tell us what you are working on, as well as if it has 3-button or 4-button controls. Welcome to the site.