ok got a 98 blazer, 255km's and runs pretty good. In the spring I lost 4hi, I've been still doing my overlanding all summer but just slap it in 4lo to get across any possible bad spots.

The 4lo has never failed me and I am out on most weekends. I just spent a fair bit of money getting it all tuned up and trying to get better fuel mileage....ended being a $5.85 fuel filter....it was plugged and took away all my power.

Now I am doing snow removal this winter so I need to be able to get to my machine in a fair bit of snow and 4lo is just too slow to drive there and I need to get on the highway.

 

From what i've read on the net on elect 4wd you might try pulling the tccm fuse for over three min {some say three min others say for a hour or so}or unhooking the neg battery cable, then after fuse is back in or the neg cable is back on cycle the ing. switch from on to off five times {do not start the vehicle} This will clear the codes stored in the tccm and reset it - Might be worth a try