both of  737 does not function autopilot until  120 flight level after that i can turn on , how resolve this problem ?

First: Welcome to the forum.please note that PMDG requires us to sign our posts with our full name, first and last.Otherwise they will probably delete your post.

second: Without any information I can only tell you to do sit ups and run around the house. Please provide as many information as possible about your flight preparation, settings, other addons. 

Make sure you have flown both tutorial flights at least once to make sure you're familiar with the airplane. 

Edited October 24, 20187 yr by Ephedrin