Slick 60's

Defroster doesn't seem to blow very hard, the hoses look brand new to me and seems to come out of the floor fine, any suggestion?

The defroster door is not sealing. Either not moving far enough, or it's damaged. Or there's a "stinkem" or a ball point pen or some other obstruction blocking it. Crap can fall down the defroster grilles and eventually get far enough to stop the door from closing. Could even be a mouse carcass!

you should be able to feel the door with your fingers. mine didn't work very well and i found that the "heat" cable wasn't attached to anything even though the fllor heat worked good. i reached up inside the plenum and opened the door by hand. got lots of heat and defrost now.

One of the first things I do when I bring home a "new" slick is clean out the following places. 1. I take the cowl vents off and dig out, vacuum and open up the drain hole. 2.take the door panels off vacuum , scrape and open the drain holes 3. take the heater off and take it apart so I can vacuum out all the accumulated stuff that has gotten stuck there thru the years some thing about the smell of dead mice on a cold morning I don't like LOL. Also a good time to replace the heater core and hoses. Besides whenever I've cleaned out a heater box I've found money, which is really good since everything else I do seems to cost money

Where is this door at? Thanks for the tips guys, thankfully this is only a project truck so the heaters not a a major concern