Need help replacing Becker 0780 on w126
 

Hi, Guys,

I am having a problem figuring out which wires did what on this old Becker 0780 unit.
I need to know how to connect existing harness to a new Pioneer which has 8 separate wires for speakers ((2Front+2Back) x 2 wires each).
The old one does not seem to have so many wires, but it somehow controlled all speakers with only 3 black plugs connected (plus antenna wires).

Such a mistery for me! So far, I was able to find information only on plug.1 on the internet. Its pins supply power.

Can somebody help?
Please see the attached pictures.

Best regards,
Al

Just deal with the four pin, that's your power, ground, switched, and dimmer.