Steering Wheel Circuit Customisation

[JefferiesFarnol]

Hello chaps,
I've installed a new head unit from Continental which I really like, though I've struggled to get the steering controls to work. I bought one of the Connects2 interfaces but it doesn't support the Continental system.

I thought I might try to swap over the resistors on the switch board to the values they need to be for the radio so I've bought a spare switch to have a look.





I've no experience with circuit boards but I think it works like this:

Volume down: no resistor
Volume up: 391 ohm
Track up: 391 + 471ohm
Track down: 391 + 471 + 821ohm
Mode: 391 + 471 + 821 +1520ohm

This seems to correlate with the resistances for the switches that I've read on here.

Someone happily shared the approximate resistances the Continental radio uses which are these:


Volume Down: 0-10ohm
Volume Up: 110ohm
Track Up: 310ohm
Track Down: 460ohm
Mode: 165ohm

If I'm right and the mode button is a combination of all resistors, it looks like I'll struggle to get it to work just by swapping them as the mode value for the radio is not the highest value, though it looks like I may be able to get the others going. Another option I suppose would be to get a custom circuit board made. Am I right or am I over-thinking this? If there's an easier way to get this working I'd gladly hear it!