Somewhat similar to the MX-5 NC is installing cruise control on a Mazda RX-8. It’s a bit of an odd one out, but I thought it would still be fun to pull that off as well. I got that request from someone who owns both an MX-5 and an RX-8. He knew I regularly install cruise control on the MX-5.
Not standard in Europe
After doing some research online, it seemed like a doable project, so I started looking for parts. Just like with the MX-5, it turned out that the North American version often came equipped with cruise control. On the European models it was rarely used. On top of that, the manual-transmission RX-8 is rare in the United States. Most used steering wheels on the market have buttons designed for cars with automatic transmissions. Therefore, the RX-8, steering wheel-mounted buttons are very hard to find. Unless, of course, you’re willing to buy them new.
A different steering wheel
Since the original steering wheel is hard to find, we looked at alternative steering wheels. We found the steering wheel and airbag from a Mazda 6, that were built around the same time as the RX-8. The size of that steering wheel is identical to the original one. The buttons on that steering wheel also send the same signals to the ECU as the original steering wheel. Ultimately, we therefore decided to go with the sport steering wheel. It features perforated leather, and was offered on several Mazda 6 models.
The car is ready for it
On the RX-8, the cruise control is always built into the ECU. Originally, activating cruise control was easy. Installing the buttons on the steering wheel, the correct brake switch, and running the wiring was enough to get it working. When that became known, Mazda threw a wrench in the works. They disabled the software whenever the car was brought in for service at the dealership. Cruise control continued to work, only on cars that came equipped with that functionality from the factory.
Eventually, highly technical enthusiasts discovered how to re-enable it by modifying the as-built data in the ECU. However, this adjustment should only be made once all parts are installed. The wiring must be complete and the steering wheel buttons and 4-pin brake switch must be present. All versions of the Mazda RX-8 display information about the status of the cruise control system. The early versions displayed the text “cruise main” in yellow when the system was on. Then the text “cruise” in green when the system was actually regulating the speed. In later versions, only the text “cruise” is displayed, and the color of the light indicates whether the system is on (yellow) or active (green).
Need help?
If you have any questions, you can reach me via the contact page
If this information has been helpful to you and you’d like to support my work for the MX-5 community, please consider subscribing to the YouTube channel. It costs just a small amount each month. It helps me continue to invest in developing new knowledge and experience that I can then share with you.
You can find more information about this here