Date registered: Oct 2013
Vehicle: A200 Sports Coupé C169 2006
Location: Bozeat, UK
Mentioned: 2 Post(s)
Quoted: 207 Post(s)
The existing connector is not ISO - it's a Quad-Lock.
As I mentioned before on a different subforum, you're much better off getting a model-specific head unit, i.e. one designed for W169 / W245 / Sprint, et al - perfect fit, full connectivity and looks great - otherwise the cheap kit of a standard Double-DIN unit will require connectors, adaptors and frames, which in the end will cost more, than a model-specific unit.
At the very least you now need a converter: ISO to Quad-Lock ... could be up £60.
A perfectly specced modern android HU, with all the functions (including full steering wheel controls) is about £250, if that ...
There are two wires, that supply power to a head unit in Mercedes car (most of, anyway) - that's why it works when the ignition is off, but the key is still inserted.
Your ISO plug is obviously wired differently. Do you have a CANbus decoder box in the kit? If not, that's another rather expensive addition, if bought on its own.