I own a 2013 Audi A5 Coupe.

For a few months now the rear left speaker has had no sound, only a buzzing that comes and goes when it likes (almost every journey I hear it though).
This buzzing is heard when the electrics are on, no sound has to be on, nor does the engine have to be on.

When at my local garage they ran a test for me, the following codes appeared:
00876- treble speaker rear left (R14) short with ground
02558- left rear mid - range/woofer loudspeaker (R159) short with ground.

Took it to a sound place and showed this, they said it’s most likely water damage on the Amp.

Brought an identical amp off eBay, plugged in, buzzing stopped, so did all the sound down the right side of the car, left rear speaker where buzzing was, now just very feint sound but NO buzzing.

Brought another identical amp off eBay thinking this could have just been faulty also, exactly the same thing happens. No sound down right side.

Any help would be appreciated??