Shifting

I have a 1992 Blazer and I'm have problem getting it into four high it will go into four low with no problems it has a electric shifter if you shift it with the motor off you can hear it trying to move the cylinder but does not go all the way in any help will be apperciate

70D

I've got another deal I unhook the battery for five min. thenhook back up and it went into four high the first try but after I put it back into two high it would not go back into four high is My motor bad or is it computer problem

Thanks as always 70D