Nissan Repair: climate control and heater problem, plastic soda bottle, nissan maxima

Question
The climate control display is blank on my 93' Nissan Maxima. The blower motor and ac controls seem ok but the problem is with the heating.  At best the temp gets "luke warm" then seems to go cold.  I have replaced the radiator, thermostat, heater core & blend door actuator(i've noticed that it still doesn't move). I also checked all the fuses.  Replaced the climate control with a salvage piece and have the same problem. Any ideas would be greatly appreciated! 5a.m. winter mornings are getting rough without heat!!! Thanks

Answer
this generation of Maxima was brutal for getting air locks in the heating system.  after any cooling system repair on them I would always struggle to get all the air out of the cooling system.  I found the best way was to rig up some sort of funnel in the place of the rad cap also an old plastic soda bottle works, just wrap the tip with some electrical tape to fit it to the rad spout, make sure you keep a small amount of coolant in the funnel and run it with the heat on full hot, you may have to rev it up a little and if there is air it will make its way to the funnel burping out and taking new coolant in to avoid the air getting in.  CAUTION sometimes the coolant will splash out depending on how bad the air lock is, it might get a little messy, just shut the car down if this happens and wait for it to cool back down, as it cools down get ready to add some coolant back in don't let any air get in.
also under the hood if you follow the heater lines to the fire wall you will notice a small actuated valve in one of the lines.  this line may not be opening causing poor heat, try manually opening this valve to see if your heat improves, if so just rig it open for the winter.