Oko

Right.

I'm getting pretty stumped here.

My HU of choice is a Blaupunkt Queens mp56. The last picture in this post has the pinouts for it.

Problem is such; With the adapter wires (picture 3), I get loud whining noise from the speakers *when the car is running* and I press pedal. I believe this can be rectified with a condensator of a right size and at the right spot.

My main problem however is such. When I ground the wiring harness, my front speakers refuse to work. Ungrounded, my rearspeakers, the ones which give the bass on the rearshelf, refuse to work.
Fader from HU does not work then either.

Now, if I plug in the C1 (yellow part in pictures 1&2) which holds the LR-LF-RR-RF-Ground-Wakeup directly into my HU, all of this works just fine, but has a lot of static and loud pops from the amplifier. But with the harness, as I've described earlier.

I'm at a loss here.

Oko

And since I cant find the edit part, replying here myself.

How the wiring harness functions is, it takes the C1 (yellow mini-ISO) and rewires the LF-LR-RR-RF wires through a GLI (Ground Loop Isolator) into "proper" ISO-clip, which is then attached into B part of the HU. The ground and amplifier wakeup are separated into different parts.

Somehow the problem lies in the C1 -> ISO transformation, but I'm stumped as to what exactly is causing this.