headunit wiring to speakers

just got a Pioneer MVH-150UI which is ipod/usb etc..
got the nice big black standard plug with a small harness to the HU.
at the mo only the drivers side speaker works.
having had a better look at which wires were chopped off the old mini loom (no longer used as new one provided).. it is the rear speakers they wired in bypassing the main black block.
basically means i need to get the passengers door card off & check wiring back to the main black block.... or test another speaker..

A multi meter often helps you detect a speaker because they always either measure 8 ohms or 4 ohms.

Once you've worked out which are pairs.... then you can just try each pair on one of the outputs and remember which speaker it is, then wire them all up permanently.

Plus you should always test the two powers and ground, because they are not aways the right colour or pin location. When I was young and inexperienced I blew a couple of head units from making assumptions.

Only playing with the "black plug" in the diagram.
HU powers on etc all ok. Just sound out I need to sus.
Lack of time right now is an issue for several things!

The one that often catches people out is the memory - when you turn the key off it forgers the radio station settings etc. Some head units and cars have the permanent live which tends to be red or yellow in different places.