Nissan Repair: Heating/AC problem in 96 Maxima GLE, heater hose, fan motor

Question
I have a 96 Maxima GLE.  my problem is that my heat does not work.  about two months ago, i had this problem and had my thermostat replaced.  this seemed to do the trick for a while.  but then it started to happen again.  the heat gauge tends to go increasingly get hotter, but as i drive at higher speeds, it comes back to middleground.  any ideas?  also, the A/C doesn't work, so i'm assuming it's the same problem.  and i put fresh coolant into the engine, as well.  so there's no problem there.

Answer
Patrick,

Sounds like you have air trapped in the system that needs to be bled out.  At the highest point of the engine you should have a bleeder screw.  If not, you can unscrew a heater hose that is the highest and let the air run out until coolant comes out and then tighten the hose.  Also, the temperature thing sounds like your cooling fan is defective and you need to check the fan motor as well as the relay and temperature sensor that drives the fan.  The airconditioner is a different issue.  You need to see if the compressor comes on when you activate the airconditioner.  If the compressor comes on and you are not getting cold air in the cabin it could be the blend door or a blockage in the system causing the evaporator not to blow cold.  If the compressor runs and the blower inside the cabin works and the blend door moves you will have to do a system pressure check to see if there is a blockage internal to the system.