If the gauge is reading full (pinned as we call it) it can be a ground to the sending unit or the wire going to it is broken ,,this will cause this..
Sending unit wires are on top of the tank some times you can see it (or the wires that go to it )test them there you'll need a good meter!!
If you want to see what it looks like go to a parts shop and get them to show you one
Replace freeze plug in a 1998 ford windstar ?
Not likely - the 1999 Windstar was a rather significant updating of design compared to 1995-1998 models.
A 1998 Ford Windstar would use refrigerant 134a
On top of the cam sensor synchronizer which is sticking out of the top of the timing cover on the front of the engine.
On a 1998 Ford Windstar : The 3.8 liter V6 engine ( and the 3.0 ) has a timing CHAIN
Not very likely - the Windstar was significantly redesigned in 1999, and the dimensions of the vehicle were changed.
Multi functions switch is junk
On top of the cam sensor synchonizer which is sticking out of the top of the timing cover on the front of the engine.
Mostly in the Windstar category - they all apply to the GL model
On the evaporator case.
On a 1998 Ford Windstar : ( # 16 / 20 amp )
On a 1998 Ford Windstar ( 3.0 and 3.8 ) firewall 1-----2-----3 4-----5-----6 front of vehicle > driver