The heat and a/c fan comes on automatically when car is not running..
which drains the battery. Any suggestions

 

It is supposed to come on, even if the car is turned off, in warmer weather to dry out the A/C evaporator and ducts, but there is a battery voltage condition in the logic that should not allow it to drain the battery. It is called "afterblow". Other threads here have suggested a stuck relay in that circuitry could cause the issue you are experiencing.

 

yep - if the s70s are set up similar to my 850, the relay is up front by the top of the radiator.