I own a 2001 Mercury Grand Marquis, over 6 years, I've learned a few things along the way. The air conditioning system from a 1998 will bolt in, but you need a condenser sensor from the 2001. The shape of the connector changed over the years, other than that, same system.

The blower motor, relays, and fuses are interchangeable, from a 1996 F250. As odd as that sounds, yes they will work. The blower motor however, doesn't fit perfect. If you are in a pinch, it will get you by, with a bit of tweaking and duct tape.