Have 1999 Blazer with the 4.3 engine. i can engage 4hi without any problem. Can switch between 4hi and 4lo, no problem. Going from 4hi to 2wd is the problem. When I push the 2wd button, the light flashes, I hear 3 clicking sounds, the light quits blinking and the vehicle stays in 4hi. I press the button 7 or 8 times trying to disengage the 4wd and the clicking stops all together. Nothing happens. Thought maybe someone would know a solution before I started tearing by Blazer apart.

 

Try a search many people have covered this

 

I am assuming that you have the 3-button switch in the dash meaning you have the NV233.

Pull the codes and let us know what they are before you take anything apart. Follow this thread:
OBD2 NV233 Diagnostics

Once you have the codes, pull the switch in the dash, the electrical connection to the TCCM (behind the passenger side kick panel), and the electrical connections to the encoder motor (on the transfer case) and check for corrosion. Clean as necessary, lubricate & protect with dielectric grease, then put them back together.

 

i'll try that and let you know what happens. I appreciate your input on this. I'd rather pend $$$$$ on my kids for Christmas than fixing my Blazer.

 

Check the 4wd fuse first. I had sam exact symptoms- that fixed it. Just wonder why the fuse blew?