I reconnected all the electrical cables I took apart on my 2004 Mazda RX-8, intending to clear all personal data from the original navigation system before I replace it with a wireless CarPlay/Android Auto receiver. But when I turned the car back on, everything stayed dark. I found and fixed a problem with the audio control panel, caused when I used too much force upon removal. Now the audio panel works, but the navigation screen still stayed dark.

Everything electrical seemed to check out, I got as far as confirming that there's power going into the LCD control board, but nothing is moving. Normally when I power up the system, the motor whirs to unveil the screen and the screen turns on to show the navigation system boot sequence. Now I have no motor whir and the screen stayed dark. Since I'm doing just an electrical test, the motor is connected but merely sitting off to the side.

Thinking maybe I've missed a subtle detail somewhere, I kept my eyes open as I mechanically reassembled the navigation hood as well. Retrying the experiment, I was excited to see the motorized hood moving into place and the screen came on as expected. Interesting! I pressed the open/close button to verify the closing sequence, then I pressed it again to open it up. The second time, nothing moved and the screen stayed dark. What's going on?

Eventually I figured out the motor sequence will not execute if the actuator is out of its expected range of motion. This seems reasonable enough in hindsight. Such was the case when the motor was just sitting off to the side and was the case again when the partially reassembled hood closed. (When fully reassembled, the surround panel will keep it from moving that far.) The inertia from closing pushed it a little too far and out of the expected range, so it refused to run the second time. But if I push it a little bit, back within its normal range of motion, it will run.

That was good to know, and now I have the old navigation screen up, I could perform the reset sequence as per RX-8 owner forum thread:

  • Go to System menu.

  • Select Version Information.

  • Move the navigation control joystick: up, up, up, down, down, down, up, up. This should bring up a diagnostics menu.

  • Select "CD Check"

  • Select "Cold Start"

The system will reboot and, when it comes up, the "Select Destination" menu will show up with "Marked Point" and "History" grayed out: they have been erased. This was what I wanted, and I can proceed with my screen replacement project.