Fitting a connects 2 to a concert 2 today. Worked fine to start with but when I pushed the HU in it started to feedback. Now there is a crackling noise when operating volume or any other buttons on the HU
I suspect the earth so checked the black cable and orignal brown earth were connected.
Strangely the black earth cable slightly sparks when touched against the HU chasis.
Going to check that the original earth is still connected tommorow and see if it makes a difference.
Failing not sure if it is a faulty unit...