heat does not work

You need to check out the heater out, system by system. First, make sure the engine's warming up properly, the thermostat should keep it at about 185F. You can feel the heater hoses, should be hot if coolant is circulating. You need to check the controls and the acutuators in the heater enclosure and see what's not working. I recommend you find a Mazda specialist. Here's a directory link for you: http://repairpal.com/mazda-repair-in-long-pond-pennsylvania

I had the same problem on my girl friends 97 mazda millenia I found out the heater core was clogged I just disconnected the coolent out hose to the heater core its self coolant should constantly be poring out and it wasnt i hope this is helpful to you