99 Blazer Stuck in Four wheel drive

I have a 99 Blazer with electronic Four WD. I read some previous posts and replaced the switch on dashboard. Still in 4WD HI. It wont go into 4LO or 2HI. I removed battery and pan, started vehicle and watched the vaccuum axle actuator operate. It is functioning properly as far as I can tell. Any advise would be appreciated.
Any ideas?

I also have a 99 blazer with auto 4wd that is stuck in 4wHI. If you search past posts on this topic your will learn that there are a number of things that can cause this condition and the fix can be as simple as replacing a fuse to as expensive as replacing the transfer case encoder motor or the 4x4 computer(TCCM). Until your vehicle is properly diagnosed and repaired you can make the truck driveable by disconnecting the vacuum line between the frt axle clutch solenoid (firewall) and the frt axle actuator (under battery). This will disengage the rt frt wheel from the frt differential effectively allowing the drivetrain to operate on dry pavement.

Yes you can disconnect the vaccuum line, and it will disengage the front diffential, but don't forget the transfer case is still engaged, and with that, the front axle is still engaged, so its a short term solution.

Try this before you disconnect the vacuum hose. Turn the switch off and pull the fuse marked T-case (it should be a 20 amp) wait about 5 minutes and replace the fuse. After it is replaced turn the ignition switch on and off 5 times then start the engine and push the 4 Wheel HI button. If it works you saved yourself some money just be sure to exercise your system so it will perform correctly, I do mine about once a month or when I change oil and I am taking it for the warm up spin. If the problem returns your system needs to have diagnostics ran on it to pull up the codes.