1994 4x4 won't shift into 4wheel high

hello all

i have a 1994 s-10 blazer 4x4 4.3 cpi
it will not shift into 4 wheel drive high
it will shift into low and out of low
and both of the lights on the switch(green for high and yellow for low)
light up when it shifts into low range
and sometimes the lights on the switch light up on there
own but no shift at the trnsfer case
please help

also
i had replaced ball joints
and left the abs sensor wires up to high
and the rubbed thru on rim
now abs light is on
i fixed the wires with but connectors but abs light is still on
and i cant clear the codes