The heater control units are failing on Mazda RX8. When driving the air goes hot to cold back and forth. If you move the knob back and forth you can get your heat back. I have had windows fog up because the heat has gone out. I have contacted Mazda and they will not address it. I am not the only person this affects. If you do a search on rx8club.com you will see all the failures.

- Cheyenne, WY, USA

Ac and general cabin temperature problems. I am having a combination of problems with the heating and cooling of the car. In the summer when it is very hot there is a noticeable "pulsing" or on/off symptom of the cold air generated by the ac. I timed it and very cold air comes out of the vent for about 30 - 45 seconds. Then it is followed by about the same duration of regular air (the ac seems to shut off) so on hot days you get a pulse of cold followed up by a pulse of warm air. The effect is that the cabin heats up and the ac cannot keep up with it. It the winter when it is cold out there is a different issue. It seems that the vents are allowing outside air to get into the mixture. In the winter ice cold air is being mixed in with the heat which has the same effect where the heater cannot keep up with heating the cabin of the car. There is also an annoying feature on the defroster. You cannot defrost the window with inside air as soon as you turn on the defroster it flips the outside air vent open. So when it is very cold you have to chose between seeing out the wind shield and freezing or heat the cabin and the wind shield fogs up. I have taken the car in three times and have since gave up. The tech's obviously cannot or will not fix it. The tech actually had a thermometer in the vent of the car and of course the car is inside the garage in the shade. So he pops in the thermometer and comes back and checks it a - ok. I gave them a detailed description, do you think they took the car out and drove it when it is above 85 degrees outside? nope

- Broomfield, CO, USA