I recently purchased a 4 channel relay module and a start button from a Mazda 3. The relay module cost me $8.49(USD) from Sain Store on Amazon.com. The Mazda 3 start button cost $25.00 off ebay.

I tested all the pins on the start button to figure out what each one did. Luckily it’s a fairly simple button.  On the inside it has 6 LEDs and 2 switches. I really like the status lights that this button has(ACC, ON,  2 color center light). There are 5 amber/red-ish LEDs – 1 for ACC, 1 for ON, 1 for the center light, and 2 for night time illumination. Then there is 1 green LED for the center light.

After finding a pin for each function I didn’t care to figure out what pin 10 went to. It might got to nothing, or it might also be a switch pin, or a signal out. Who cares? Anyway, here’s my findings: