my 4hi is not working recently replaced the push button switch and the acuatar switch on front axel, 4hi worked for awhile then stopped workin when i tried it out a couple times after testing it, could i need a new encoder motor?

I have disconnected the battery before in winter when it wasn't working. got to work. but after winter it stopped workin on me. though 4 low works and i can switch out of 4hi into 2 when 4hi is not engaging.

 

it could either be the vaccum colector at the axle or the actuator underneath the hood.

 

is the vacuum collector next to the acuator switch on front axel? my s10 blazer is a 92 if that helps out too, and i checked the acuator under the battery the vacuum seem to be workin and there are no leaks i believe.