Fan is still on with no key

My fan behind the 3rd row seat passenger side
only is now running while the key is out. I've tried
the 2nd row buttons the dash button s and steering
wheel button s while car on to shut off. It was
never on before. But today I put seats down in 3rd
row. I see no switch or anything back there and the
fan only stops when I disconnected the battery. It's
disconnected for the night for a theory to reset the
computer I don't think that is the case. But they
seats have been down all day for the first time
since I owned it and i just noticed it after 9 pm. Any
ideas? Please and thanks in advance. Not sure
exact model but it's a 2002 envoy with 4 wheel
drive