Recently, I had an issue with my 2005 Mazda RX-8 Climate Control Unit. Last summer in Las Vegas, the unit would not kick on the AC unit and blow cold air. When the AC was enabled, the climate control still blew hot air instead of cold. As a band-aide to get through the summer I found that if I turned the AC knob as far as it would go counter clockwise (towards cold) OR clockwise (towards hot), the Climate Control unit would work and blow cold air. However, every now and then I’d have to turn the knob again far clockwise or counter clockwise when the air would sudden start blowing 120degree heat on my face in the middle of the Las Vegas summer.
After limping my way through the summer, once the temperature began to cool down for Winter I had a new issue. Now, I couldn’t get the heat to turn on at all. The climate control system would just blow cold air. It did not matter what setting I had the knobs set as. I tried my “fix” that I used over the summer, turning the knob far clockwise or counter-clockwise, but unfortunately the unit still kept blowing cold air. This was not fun driving to work on mornings when it was 35° F outside. Contrary to popular believe, it gets cold in Las Vegas during the winter nights and mornings. Being in the desert we have high temperature variances. In the winter, it could be 60 degrees for the high during the day but drop to mid-30’s during the night.
So I did a bit of research and checked the price for a new climate control unit (about $300USD). Others appeared to have the same issue with their Mazda RX-8’s. My research appeared to point to bad solder joints. So, I disassembled the climate control unit which was a bit of a pain. I had to take my gear-shifter apart, the center console apart and the dash apart in order to get the climate control unit free. After doing so, I was able to disassemble the climate control unit and check out the PCB (printed circuit board). The temperature selection knob is just a potentiometer soldered to this PCB. I found that there were very hard to see hair-line fractures in the three solder joints for this potentiometer. After heating up the solder and letting it re-flow and reassembling my vehicle, I have not had a single issue with the climate control system and saved myself $300 on a new unit. I hope you found this informative and thanks for visiting!