Dryer controls can bet set but start button does not work.
You will want to check the thermal fuse on the blower housing to make sure that it checks good for continuity. If not then the thermal fuse would need to be replaced. If it checks ok then the user interface would be the cause for the issue.
As soon the door is closed the dryer goes on after selection of heat settings the dryer doesn't shot off
The dryer starting as soon as the door is closed and the heat selected but not hitting start would be an indication of a faulty electronic timer kit. The part number for the timer kit is R9800176 but has been discontinued by the manufacturer with no replacement available.