1995 chevy blazer 4 wheel drive not engaging

ok i have a 1995 chevy blazer 4x4 with the 4.3L vortec engine. it has the buttons on the dash to shift to 2HI 4HI and 4LO. when i start it the lights al light up for the switch and then all go out. when i shift int drive none of the lights for the 4wd light up. if i put it in neutral and press the 4HI button it flashes 5 or 6 times and then lights up the 2HI button. when i press the 4LO button again it flashes

5 or 6 times and then lights up both the 4HI button and the 4LO button. i was hoping someone would know what is going on and could help me out thanks.