1997 E350 heater/AC problem
 

I bought this van a few months ago. When I first got it the heater worked fine but the AC only worked sometimes. Now neither the heater or the AC works. The blower works fine. Plenty of air blowing out. Just no hot or cold. Any ideas? Thanks.

Their are vacume lines that open and close doors to let air in they control weather you are using air or heater, Also are the hoses hot going to the heater core.One other thing if this van was sitting a long time not being used mice build nests in their.