switch problem??? on 1995 Cadillac Seville STS

A fan behind the motor in my Cadillac started running last night... the car hadn't been cranked in 2 days..surprised to hear this noise coming from garage. I undone battery cable to get it stopped then today when it was reconnect blower fan didn't come back on but the AC would come on...
I just had a new AC unit put in 9 months I
think it must be a fuse or switch problem...any suggestions of what I might be dealing with..Thanks.

Asked by for the 1995 Cadillac Seville STS
The Blower Motors on these Caddy cars have real problems, the electronics tend to short out and then the Blower Motor will come on in the middle of the night. Need to get new Blower Motor.
2 more answers
My 95 Seville started doing the same two weeks ago. With the switch off, the AC fan and radio are operating. I was getting a 'switch problem' message on the information display. It may be the switch, will followup when I get it fixed. ken
Well, I took it on to shop and it cost me close to $500.00 ):..It was a module
that controls several functions. Labor wasn't bad but part cost $381.00.
Now I have a loud noise coming from behind the dash when the AC
is running.......wasn't there before ???? Had AC system replaced last
fall so it should be in good shape. This car has 175,000 and still drives
like it was brand new. Have a oil leak from around back seal but haven't
been in a hurry to get fixed ...was told to just drive it for now.