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Steering wheel controls - CAN bus or resistive?

91 Views 3 Replies 2 Participants Last post by  GDCobra
Hi all

I'm just trying to work out how the head unit gets data from the steering wheel controls, there are very few wires unaccounted for on the connection to the unit so obviously not 1 wire per function (5 switches on wheel), from what I've read these can either be CAN but or resistive. Do we know which?

On the unit there are 3 wires connected to a SENSE socket, I'm assuming some or all of these are involved. Is that correct and if so which are they?
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OK, I think I've found the information so I'll answer this myself for the benefit of anyone lookin for this in future.

I should have made it clear in my original question that my unit is the double DIN Tomtom head which is a Panasonic device:
Font Rectangle Signage Label Electric blue

This is fitted in a 2013 NC (3.75) model, not sure how standard the wiring to the car's socket is.

It seems that on this car the steering wheel control is resistive (presumably means each switch will be seen as a different resistance when pressed and uses 2 wires from this socket as shown in graphic.

Electrical wiring Publication Cable Font Wire


This is the rear side of the PLUG on the head unit's adaptation harness NOT the socket on the car's loom.

For completeness it seems (from what I've gathered so far) that this is known as a METRA 70-7903. Don't know if that is one manufacturers part number or the number for this 'standard' interface.

I've seen the same pin-out information in multiple places so presume it's a standard.
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Hi GD....

Not sure of the terms required, but all I remember when fitting my android system to the Vitara was connecting the plug from the Android unit to a Suzuki harness adaptor (just connect the colours)...the menu in the Android unit was 'SWC' (Steering wheel controls) and just a few clicks had them working...
Probably of no use to you!.... 🤔
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All past experience is of use Garffey and very welcome. Sounds like the unit has to go through a learning procedure to work out what the different resistances are. From what I've read some units can also differenciate between a long and a short switch press to give different response hence giving more functions. I'll find out in time and feedback here.
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