I have a 1992 , 400SE, air from the ac/heat comes out very, very slow, I was told it may need the regulator replaced, since I get some air it may not be the motor or fan, I am pretty good working on cars , but never done this test,
Question: what is the best way to test this? mainly where is the regulator located, and how do I replace it?

Please help!!!!!!!!!!!!!!

John