Two problems related to electrical system have been reported for the 2005 Mazda RX8. The most recently reported issues are listed below.
Failure of clutch pedal assembly. A plastic plate cracked and caused an irritating plastic binding noise, ever time I released the clutch pedal. This apparently happens a lot, sometimes it is fixable but in my case I had to replace my entire assembly, as I was told if it completely cracked I would lose the function of my clutch pedal. Failure of the passenger side power lock actuator. I have read many accounts of this part failing. Usually blamed on hot or cold claimant, however mine just failed earlier this week, with weather in the mid 40's. Just from the amount of postings I found when this happened to me it needs to be reported.
The Mazda RX-8 is having an issue that is coming up more frequently now from a faulty a/c switch or heating system failure. The heat does not come into the vehicle when the heat is turned on and only cold air comes into vehicle. The failure happens in the beginning only randomly until the unit completely fails. The a/c modular is a electronic switch that changes vents and a/c or heat. The vent mechanism still functions but the heat is never transferred into the vehicle. The consequences from this item failing, especially in the winter time, the windshield cannot be defrosted and driving down the road way human exhaustion will cause the window fog up impairing driver's vision. As well as cold temperatures within the vehicle that do not suffice while driving in cold weather.