I'm not a fan of drilling into things and slapping aftermarket switches on the dash. However I do like adding things to my car which necessitate a separate switch to be used. My purpose for this mod was to activate my recently installed headlight washers, however this same setup could be utilized for countless other purposes.
The switch panel to the left of the steering wheel has a blank next to the VDC off button. The face of it is sloped making it impossible to simply drill or cut and pop a switch into it, at least not without cutting up the back side of the panel to make room.
For this project you'll need the following:
Switch https://www.amazon.com/dp/B06XGTJK7S..._8nJsEbVFR46WG
Small hacksaw
Assorted sandpaper
Tesa tape
I'm using this as a "before" photo but in reality this is the completed project with the switch installed
First you'll need to remove the blank. A small flatblade can be used to pry up the tabs (2 on top, 1 on bottom) and then push it through the back of the panel. Once removed it looks like this:
Once removed you'll cut it as shown. I used a small hacksaw which worked great. Set the front portion aside for now. Take the back portion and clean up the cut surface with some sandpaper, getting the surface to be flat and smooth.
Next take a switch and cut the locking tabs off. Sand it smooth and check the fit in the back half of the switch blank you just cut. It needs to fit flush but it's fine if it's snug. You could glue it in place but mine fit snugly enough to not need any. Once complete set this part aside.
Now take the front portion of the blank and cut off a slice equal to the thickness of the switch. I didn't measure anything but rather marked it with a razor while up next to the switch and then cut it with a hacksaw again. Just like with the back half sand it smooth.
Drop the front half into the switch blank slot and test how well it slides. It will need to move forward and back freely but not be loose to the point of rattling. I used some very fine sandpaper to sand the sides of it as it was just a tad stiff. Test before doing anything and sand a little at a time.
Once you get a satisfactory fit on the front portion, snap the back half into place. You want for the switch button to be snug up against the front half to avoid it rattling. Mine had a tiny bit of play so I put 2 layers of Tesa tape in between which made it perfect. This is another step that requires testing and minor adjustments until you get it just right.
After getting the fitment perfected you're done! See the first photo for the completed product. It's hidden in plain sight and maintains a clean, stock looking interior. But instead of being just a dummy blank, it now functions as a momentary switch when you push on it. With some trial and error I got the perfect amount of resistance without it being too loose and rattling or too tight and sticking. It has a very tactile feel and enough travel to let you know that you're pushing it. Hooked up spade terminals on the back and it's now used to activate my headlight washers.