Not sure about the 92s but the 91s HVAC controls on the back has a rotating selector gear which turns and selects the correct vacuumn line when the lever on the face is moved back and forth. I took mine apart a while back and never figured out how to put it back together and everytime I turn my car on it makes a hissing sound coming from the vacuumn lines . So maybe you also damaged this part when you gutted your interior?
Sorry if the description is kinda vague, maybe someone else can clarify.
Sorry if the description is kinda vague, maybe someone else can clarify.