05 S4 - noise when sidelights on

[pablo]

Hey all, installed my alpine headunit into my s4 but have a problem with noise when the sidelights are on. The unit was in my old car and was fine.

Firstly tried wired direct to loom and phono adapters to make the bose work. Ign fed from fusebox.
Replaced the loom with an all in one to get canbus/steering wheel controls. Noise the same.

Note this happens with engine OFF or on so not alternator whine. I have xenons but noise comes when sidelights are turned on so not xenons.

I earthed the headunit to a good spot behind glovebox made no difference.

If i unplug all 4 phone cables there is no noise. As soon as i plug one in (any) the noise starts.

Doing my head in. Any advice?

Thanks

 

[AlexA4Avant]

Try a ground loop isolator but it's amplifier buzz try turning the output down on the head unit. The phone leads are running near your side light cable. Route the phonos on the left hand side of the centre console.

 

[pablo]

Its a constant noise at any volume even 0.
Phonos only run into the car loom behind the HU so no scope to reroute. I tried pulling the hu out and having all the non oem loom bits out from the dash but still same.

Im going to reconnect the std hu just to confirm its not something else.

 

[AlexA4Avant]

Put a ground loop isolator they're only a few pounds. Are they the standard bose phono leads

 

[pablo]

its this adapter loom

also tried this one originally (top part):

 

[AlexA4Avant]

Looks complicated good luck