cold to hot not wotking

[Madme]

Ok so my AC works fine and have been using it all summer. Tonight i tried switching it to hot and no heat only got cold air. Tried switching it back and forth cold to hot and eventually it change to hot. Now my problem is that it won't go back to cold.

Would this be a problem with the temp controls or something further in?
1990 Town car

 

[slowmkviii]

blend door motor maybe

 

[Madme]

I guess that it was because i didn't use it all summer. So now the problem is that i set it 70 and the temp goes to hot and cold by itself. It won't stay constant.

 

[mrzeee]

i do not sell many blend door motors for the t/c but they are available. They retail for 40.00 and lvc cost is 28.00 plus shipping. Is there a test or diag function on the t/c heater control head?? you might want to search that out.
max