Fuel pump is alawys on on 1990 Mercury Cougar

Hi, my car is a 1988 Mercury Cougar. It has a V8 engine in it and a 5.0 liter. My fuel pump is always on, we thought it was a relay problem and found out it wasn't the relay problem. So every night before we go to bed we have to disconnect the battery. Does anyone know what it could be?

Asked by for the 1990 Mercury Cougar
Did you really , really check the GREEN fuel pump relay behind the glove box, they do this, so be sure that is the one that you checked. If you unplugged that and the pump still runs, then->>

here is link to a repair manual web site, it will have a picture and instructions.