If you have a stereo system with the Boston Acoustics amplifier
and an annoying high pitched whine, this is how I remedied mine
Purchase good
quality shielded audio cable
Disconnected battery
Removed headunit fascia
Removed headunit
Remove fan control panel
Removed centre console
Removed passenger seat
Removed rear seat base
Removed rear passenger lower door trim
Removed rear passenger C pillar seat belt trim
Removed wagon lower door mould
Removed wagon upper door mould
Removed wagon floor
Removed left hand upper D pillar wagon trim
Remove left hand wagon trim
Laid new speaker cable from head unit, alongside hand brake,
under carpet, under rear seat, under rear insulation, to amplifier.
Located dashboard wiring harness for stereo
Cut four wires
green / violet
green / dark blue
white / tan
white / blue
Trimmed all extra shielding from this end
Paired wires to same colours at front connection of amplifier
All shielding was earthed at amplifier end
ALL connections were soldered
Reconnected front passenger seat
Reconnected fan control panel
Reconnect amplifier
Reconnected head unit
Reconnected battery
Enjoyed whine free stereo
Disconnected battery
Reassembled interior
Hope that helps
Cheers