4x4 being weird

ive seached the forums and most of the stuff ive seen was about vacuum lines and stuff. i have a 98 blazer LT 4x4 with the electric transfer case and whenever i push the 4 hi or 4 lo from 2hi it flashes for a while then just stays on 2hi, i can hear what i think is the tccm clicking, i can hear no noise coming from around the transfer case during all this, all the fuses are good. is there a connection somewhere i can check. i dont think it would be a vacuum line because when it does work, the motor doesnt need to be running for it to engage any help?

Somebody correct me if I'm wrong please.

To shift from 2Hi to 4Hi you need to be moving. Then to shift from 4Hi to 4Lo you need to be stopped.

2hi to 4hi any speed, any hi to 4 lo you need to be in neutral either stopped or moving 3-5 mph, so says the manual

it sounds like your encoder motor or sometimes called electric shift motor went bad.mine did the same thing.if you can,find one from a junk yard or used car parts place.i know that a brand new one runs about $500.