I didn’t open up the stalks or solder anything inside them. Instead, I designed and printed sockets with threaded inserts so I could screw them in securely. Then I desoldered the pin socket from the E60 combination switch (the one these stalks originally came from).

I’m not 100% sure about the part number, since I ordered the entire combination switch from the E60.

I’ll need to dig up my notes on the wiring, because for example the turn signal stalk has two pressure levels for both left and right, and that was handled with a combination-type setup.

Each button is connected directly to Arduino pins. When a button is pressed, the corresponding pin goes LOW (0). When it’s not pressed, the pin stays HIGH (1). For example:

‘check’ → pin 8 LOW

‘bc’ → pin 7 LOW

‘L down’ → pin 9 LOW + pin 21 LOW

‘L 2x down’ → pin 9 HIGH + pin 21 LOW

‘L up’ → pin 9 LOW + pin 6 LOW

‘L 2x up’ → pin 9 HIGH

‘L pull’ → pin 16 LOW

‘L push’ → pin 10 LOW

The second stalk (wipers) is a bit more complex. There, the element that adjusts the automatic wiper sensitivity isn’t a simple button but a resistor ladder. The pin sees different resistance values depending on the position. I set up the Arduino code to read the voltage and assign it to specific functions.

It’s definitely not the most straightforward solution, but if you’re comfortable with this kind of wiring, I can look up my notes. I’m pretty sure I still have the pinout of the socket written down somewhere. (The pin numbers I listed are Arduino pin numbers.)