Heating (HEVAC)

Can someone tell me if my hevac is the problem? I put it on auto, and it will switch to Manual, press it again and it switched to manual again, 3 time it stayed that way (on auto) book comes on, stop the car, switch it off, and start it back up, book will go, then after 5 mins will come on again, do the same it will go again, all this time if the book comes up, the motors wont flow out air until I reset it with the stop start again, after about 1/2 hour seems to work ok and stay on auto... I had to pull over on the motorway all the time to re set it this way... thanks

I always run mine on manual. Could be the problem is a sticking blend motor, when it finds it won't adjust, it flips to manual. Just guessing.

Sounds about right ty