Ford mustang specs

https://mustangforums.com/forum/4-6l-1996-2004-modular-mustang/702072-shift-control-solenoid.html

If u go to the web link below u will find the procedure for replacing the heater with pictures, this applies to 1979-1993 Fox Body model years


http://www.mylrs.com/blogs/lrs/archive/2009/03/31/1979-1993-Fox-Mustang-Heater-Core-Replacement.aspx

You have to pull the inside trim off to get access to the nuts that hold the 1/4 glass in place.

I better way of attacking your problem is to tape off the molding and paint it still attached to the car. I have done this several times with very good results.

Remove windshield and rear window to do it properly. Headliner is actually crimped in between window gaskets and roof edge. Not a job for the faint at heart. If you don't know the string trick to get your gaskets in place you'll be working on it this time next year. Look on CJ Pony parts web site. They used to have a good tech article on headliner replacement. Hope this helps...

I'd check to make sure the window regulators are ok,and not damaged.
Tony
www.foxbodyconnection.com