Thread: MDM retrofit
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      09-20-2025, 09:32 AM   #4
amg6975
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Quote:
Originally Posted by kolosy View Post
Paging amg6975
You rang?

I don’t think this problem is as simple as measure and stick in a resistor. You need to take into account the resistance of the button and wires, etc. I think the OEM button circuits are actually current sources, not just plain resistances. The 12V can vary a lot and is very noisy so different resistances will look different at different voltages. There were a bunch of FETs in the OEM wheel but I never really bothered to look too deep into it when I looked at mine. I also think there is a base current/resistance and not just an open, but it’s been a while since I looked at it.

For a first pass let’s assume the button and stuff has a few ohms of resistance so give a 75ohm resistor a try. If that still only kind of works try 68 ohm. I’ll report back with more info sometime this week when I can get something set up in the lab to test.
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