i own a 1992 s10 blazer 4.3 liter cpi push button 4x4 4door vin is Z and the 4hi is not working i checked the acuator under the battery and seems to be fine and i replaced the push button switch still no 4hi, and replaced the switch underneath the axel got 4hi to work after that i wanted to make sure it was working switched out of 4hi to 2wheel then put back in 4hi and 4hi did not work after that i took out the switch and cleaned inside were the swich goes still no 4hi, and i even check the tccm fuse, fuse was good was not burnt out, could this be a encoder motor problem?