94 Jimmy 4 Wheel Drive problem

So i have a '94 Jimmy that has the 4 wheel drive switch on the dash standard red light for 4low and green light for 4high.

When things start to get wonky i'll be in in neutral select4low i get out of my driveway and when i try to select 4high it blinks makes noises and both lights go off. But as i pull away i can plainly see i'm still in 4low. My rpm's jump and it sounds like the jimmys about to blow. I play the neutral select 4low, drive back to neutral select 4high and back and forth till it fully disengages.

When the jimmy's in this state 4high will NOT come on at all.

So by chance the battery ran low on day, jumped it and surprisingly everything was back to normal 4low and 4high worked like they should no games working the 1st time i push the button.

Few weeks go by same problems start having another chance of fate battery dies jumped it and then i noticed 4wheel works again.

I've gone threw this 3 times now. Whenever 4wheel drive disappears i disconnect the battery and it works like a charm.. Anyone have a clue how i stop this!! I just want the thing to work..

yah when you unhook battery that reset's the computer so it would be ohkay and wok like it's suppose to. are you sure you got a good ground? how long do you leave neg cable off before you put it back on? if your not leaving it off for about 15 mins. do that and make sure cables are clean on cable inside the cable it's self also and see if you have any green looking to cables. but it all leads back to cables or computer.