I don't understand
None of it make any sense to me.
I think there is something you are not telling us.
Box don't get cold enough but when you replace termination fan delay
The box drop?
When u turn off the fan you had an idea?
It's not flashing gas?
Let me guess
You are working on your own equipment.
You don't want to call the tech back ( too expensive)
So you will fix it yourself.