My Jimmy wont shift out of second gear and its not the transmission. What is it?

Some early s-10 Blazers and jimmys had an electronic shift pattern . There is a small plate on the side of transmission . If you remove the cover there is a reset switch that can be reset by taking a ink pen or pencil and press the switch to reset . If it is a newer model there is a shift control module , hold on to your wallet these are extremely high priced . Hope this helps . Rick