Nissan Repair: 1992 Nissan Maxima Heater Controls, center vent, chilton manual

Question
QUESTION: My heater is not working correctly.  When it is set to blow hot air out just the face vents, the left vent and the left center vent blow hot air while the right center vent blows warm air and the right vent blows cold air.  If I select floor/face hot air comes out both floor vents and the left 2 face vents and the right center vent blows warm air and the right vent blows clod air.  On any other setting cold air comes out all the face vents while hot air will come out the defrost vents or the floor vents depending on what setting is selected.  Any ideas to what the problem maybe?

ANSWER: Russell,

In my estimation I would say the master heater/airconditioner control is defective or the lines connecting to the blend door motors are cracked or have come off.  If your system is electronic the master unit is most probably the issue.

---------- FOLLOW-UP ----------

QUESTION: I believe my system is electronic, it is all push buttons
except for the temp control which is a lever.  You referred to the master/a/c control.  Are you referring to the control box/control base/control amp assembly?  I believe there is a diagram of it on page 6-11 of the Chilton manual?

Answer
Russell,

If yours is electronic it will have a digital display and if it does the control box or control amp assembly is usually the problem.  Basically, the computer goes nuts and it does not know where to place the blend doors so you get the strange action and air coming out where it is not supposed to.  A wrecking yard is a good source since, if you could find the parts new, they would cost way too much...