I don’t know. The seat position control switches that would have been on the door were definitely on a CAN bus. I don’t have those switches. The switches I am trying to reuse are embedded in the seat itself and are there to control a complicated massage feature. I can read variable resistance with a multimeter on those switches. Those switches do not feed the microprocessor used to control the seat position motors (although they could feed a second microprocessor in the seat back—haven’t been able to take the seat back off yet).

I was asking @shortbus because I'm not familiar with any aspect of canbus that would allow specific resistances or any passive components to be interpreted as canbus messages. Canbus messages are digital communications, and can (as far as I know) only be sent or received from active devices, of which a switch cluster with internal resistors (I assume that's what it is) is not. It seemed in post #14 he was suggesting otherwise, I assumed I mistook his meaning, then he seemed to affirm it in post #17. Now I'm wondering how big the holes in my knowledge are.

 

Unless someone can come up with a proper Schematic Diagram of the Seat-Switches,
there is no point in pursuing the use of the original Switch-Cluster/Plate.

If the Car that the Seats came out of was less than ~10-years old,
be prepared to shell-out HUGE money for a Factory Manual to find out how the Switches work.
If the Car was older than ~10-years, you "might" find an online version for a reasonable price.

If it were my problem, I'd start by attempting to carefully disassemble the Seat-Switches
to see if it's possible to separate the Switches, or at the very least, remove the Resistors etc.,
and solder in my own wires.
If it is found to be impossible to gain access to the Switches for rewiring,
start planning on creating your own new Switch-Panel.
High-Quality, Miniature, "Mom-OFF-Mom", Switches, are easy to find, and very unobtrusive.

The rest is easy............
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. Are you saying that the variable resistance signal output from the switch cluster is a canbus signal?

I'm just assuming that it is. The big reason for CANBUS was to try to limit the number of wires in a car. If the BCM can decipher the different resistances as a "message" "address"(don't know the real words for it) to the BCM that would make sense to me. But my wife also tells me have little sense.

My understanding of CANBUS is that it's similar to multiplexing a signal and needs an "address" for the controller to select what to do.

I also don't understand why the TS thinks it would take so many switches to do this old school. My new car has power seats and controls all of it's movement with 3 switches. Those 3 switches do have some added movements, like they can move up, down, left , right or can be rotated a few degrees. Kind of like the way a old video game switch worked. Or the ones in a RC model controller.

 

I'm just assuming that it is. The big reason for CANBUS was to try to limit the number of wires in a car. If the BCM can decipher the different resistances as a "message" "address"(don't know the real words for it) to the BCM that would make sense to me. But my wife also tells me have little sense.

My understanding of CANBUS is that it's similar to multiplexing a signal and needs an "address" for the controller to select what to do.

I also don't understand why the TS thinks it would take so many switches to do this old school. My new car has power seats and controls all of it's movement with 3 switches. Those 3 switches do have some added movements, like they can move up, down, left , right or can be rotated a few degrees. Kind of like the way a old video game switch worked. Or the ones in a RC model controller.

Canbus sends packets of information like serial communication, with address/ID, a few bytes of data, CRC, etc. and a resistor network can't provide any of that. I think all that needs to be decoded is the resistor value to reveal which button is pushed. The only complication I see is handling the case where someone pushes more than one button at a time*.

*that, and handling pulse counting, overcurrent detection, etc, which is why I originally did (and still do) recommend a microcontroller, however I do not think it is strictly required to make the seat motors move.

 

I've said what I know or I guess, don't know.

 

Mercedes-Benz CAN-Buss Schematic Wiring Diagram ................
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