89 Maxima Heating issues

I have a heating problem with my 89 Maxima. When I turn the heat on and put the vent on floor heat cold air blows out the top vents in addition to the floor vents not heating well. I have to turn on the defrost and close off the top vents to get any heat. It is almost like there is a hole or something in the vent work. Any suggestions, could it be a sensor.


Thanks

Ummmmmm................I though I answered this question already. :confused: Anyways, there is a lever on the right side of your A/C button, push the lever down, south. And the button on the left side of your A/C button, push it to were the light comes on. Good Luck!!!

This answer may be a little late fo you but there was a problem with the '90 Maximas thermostat. The silicon used to seal the thermostat was put on a little too heavy at the factory. Sometimes when the system is flushed a small piece tears loose and sticks the thermostat open - just enough to screw up the heat without being noticable on the temperature guage. Might be worth a look on your '89?