Programming M button to an aftermarket button

[wahwill]

I plan on installing an aftermarket steering wheel and wondering if there’s a way to program the m button to an aftermarket button.

I thought it would be as straight forward as tracing and replicating the wiring, but it appears the stock button triggers multiple signals on the circuit board to send a special signal.

[Redd]

Race wheels like KMP have an external button for M button, so I don't see why not?

[wahwill]

Originally Posted by Redd

Race wheels like KMP have an external button for M button, so I don't see why not?

Yeah seems like KMP is the only available solution to this right now.

Anyone know how to DIY this? Haven’t been able to find anything on it.

[derbo]

Originally Posted by wahwill

Yeah seems like KMP is the only available solution to this right now.

Anyone know how to DIY this? Haven’t been able to find anything on it.

You probably need to learn CANBUS and how to send and receive signals via the multiplexer signals. You can probably use a CANBUS sniffer and determine those items.

[amg6975]

The M Button triggers the SZL to send an on/off CAN packet that the DME picks up, and updates it's broadcast of the mode selection packet. You would need to inject the CAN packet from the SZL onto the CAN to make an external button work.

The other buttons on the steering wheel work by creating a constant current loop that goes directly through the clock spring to the JBBF.

[MineralWhiteF80]

The face I make when I realize the M Button triggers the SZL to send an on/off CAN packet that the DME picks up, and updates it's broadcast of the mode selection packet, and it's literally the only important button on the steering wheel that I need.