Where to find steering wheel controls?
 

I'll be swapping out my stock radio for an aftermarket unit this weekend and I'm trying to do some preparation. Any tips or how-to info would be greatly appreciated.

The biggest question I have at this point is where to find the connection for the steeing wheel controls. I've ordered the Metra Axxess ASWC Universal Steering Wheel Control Interface but I don't know if this goes behind the steering wheel or back behind the head unit or somewhere else.

I'll do some pictures along the way so perhaps I can do my own How-To for others' benefit. I'm adding an iPhone compatible unit with Bluetooth for the phone, steering wheel controls, GPS antenna, backup camera...the whole shebang!

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Bond