It took 3 weeks of emails to dealers, Mazda, and manufacturers, as well as a few phone calls to Mazda USA and manufacturers in Japan, but I found a fix for the 'no manual mode' automatic transmission problem on recent Mazdas.
I've been running this switch in my car for 2.5 years with not one failure of engaging or staying in manual mode. It's also been in other Mazdas for up to 2.5 years with no failures.
Per Mazda USA, you can NOT buy the switch separately from Mazda; it only comes as part of a full shifter assembly:"I was able to look into the concern that you are having with your vehicle. Unfortunately, the piece that you need is not available on its own. You would need to purchase the entire select lever." The two prices I was quoted by Mazda dealers was $175 for a popular online dealer, and $290 from a local dealer.
(My) switch is a direct replacement for the Mazda piece, which you cannot buy. And, as Yuki puts it on the OEM switch: "....(it) is a custom product for an exclusive customer. Therefore, we are unable to offer you this item."
So, I am selling a direct replacement switch for the first generation, automatic cars. It fits the 4, 5 and 6 speed cars. Because Mazda has never sold the part separately, I cannot tell you a part number. (And, along those lines, I've also been told it will work in other recent Mazdas with ActiveMatic shifters, including the 3, 5, 6, MX-5/Miata, CX-7 and CX-9. With no part number I can't tell you for certain) You need to visibly verify my switch matches yours. I am 90% certain all RX-8 use a different switch.
For $35 you get 1 switch, and that includes USPS Priority Mail 2-3 day shipping. If you need 2, it's $45, incl shipping. That is to the continental US. Canada and elsewhere will depend on what shipping costs and hassles there would be.
If your problem is that you physically put your shifter into the manual gate and your dash display does not switch to Manual mode, or your car will not stay in manual mode when the shifter is physically in the gate, this is your fix.
I'd prefer PayPal, but if you want to pay by check or money order, I can give you my address.