When I first installed the android head unit I couldn't get the steering wheel controls to work even though they should have worked out of the box as far as I could tell. That was a long day so I gave up on SWC and buttoned everything up.
This android head unit does not have a physical volume knob and it's really hard to adjust the volume. We really wanted to have those SWC working again so I did some research and bought an aftermarket adapter to get them working. I installed the adapter, tested the buttons, and nothing, nothing change, doh.
Turns out that since our Discovery had the factory highline navigation system, the steering wheel control wires run to the back of the stereo are ibus or canbus and not just resistive controls. I spent hours working through wiring digrams trying different wiring combinations to no avail. I could see that the SWC buttons themselves were the normal resistive type, but their output whent to a control box that coverted those restive values into an ibus or canbus signal when is what the stereo got. I couldn't find any information on where that control box was located.
It finally occured to me that I should stop lookign for the control box and just tap into the SWC wires as they come out from behind the steering wheel column. I spliced into the wires at that point and ran them directly into the andriod head unit. Viola, the stereo recognized the inputs. We can now control the volume and tracks from the steering wheel again. I returned the SWC adapter I purchased since I didn't need it afterall.
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