How hard can it be to implement a dual auto-down feature?
First, let me explain what that means, because it might not ring a bell for everyone right away. It’s about how the car windows are operated. Of course, it’s great that they can be raised and lowered electrically, but there’s an even better feature. By an “auto-down” function, I mean that with a single short press of the button, the window goes all the way down. There are also plenty of cars with an “auto-up” function, but that’s a bit less common. With a dual “auto-down” function, you can open both windows completely, independently of each other.
The NB2 was the first to feature a window switch with an auto-down function for the driver. This is always handy when you want to quickly open the window all the way at a parking garage or toll booth. That feature wasn’t available for the front passenger, even though back in those days, not all of us were driving around with navigation systems in our cars yet, and we could occasionally ask a friendly passerby for directions. But what’s more important for an MX-5 driver is being able to quickly open both windows all the way so they can fully enjoy the open-air driving experience. So the NBFL had one auto-down button, not two as I’ve depicted in the photo above this post.
However, there are two versions of the window switch, because in some countries people still drive on the wrong side of the road. The electronics and mechanics in those switches are therefore different.
Meanwhile, the MX-5 community is working on a solution for the NA, NB, and NBFL models. Using an Arduino—a type of mini-computer—this solution should enable not only the auto-down function but also the auto-up function for both windows. The prototype reportedly works, but I haven’t been able to test it yet.
What I was able to test, however, was the window switch on a 2006–2008 NC with a retractable hardtop (but without keyless entry). That model has a window switch with an auto-down function for both windows. I think this is because Mazda uses an electrical signal to open the windows slightly before they open or close automatically. Just for fun, I connected that switch to my NBFL, and it worked fine, but of course, it doesn’t fit at all.
The next question was whether that switch could also be used in an NC with a soft top. The short answer is: YES
It’s actually a fun challenge for yourself to figure out, based on the different diagrams, how you could get it to work. To solve this problem, you’ll need these four diagrams.
Ultimately, it comes down to the fact that, aside from that switch, you don’t need any other parts. All the wires and the correct connector are included; only the placement of a few wires in the connector changes. If you do it wrong, you risk a short circuit 🙂
Since that switch isn’t easy to find and costs nearly €200 new, I’m also listing this modification under the “Rare” category. If you want to give it a try, look for this switch:
Since this topic comes up regularly in various Facebook groups, I made a video about it. In this video, I discuss how to perform the upgrade on an NB1 or NC.
If you have any questions, you can reach me through the contact page.
