My dad has a 1999 Bonny with climat econtrol and when you shut the key off the fan stays on, until the battery is dead. Any ideas?

Does anyone know the procedure to access the Climate OBD's?

Model years 94 and newer have to go to the dealer to read climate control diagnostics.

I assume that you have the electronic climate control rather than the manual (knobs). If so, your Blower Control Module is faulty. The BCM is located below the right hand (passenger's side) Maxifuse/relay box and is pretty easy to replace.