RX 330 Audio system wiring
 

I have a problem with an RX330 2004. Fuse 29 (30 amp) keeps blowing (audio system). Just base audio, not ML etc. Long story with the basic cause but I had a major short that blew the main 140 amp fuse and a number of other fuses but this is the only function I have been unable to revert to normal.

The radio turns on OK but there is no sound at all. When I turn the volume control it stays at 0 on the display. Same 0 whether I use the turn dial on the dash or the buttons on the steering wheel. Similarly for the bass and treble in setup.

All the other audio functions seem to work fine (eg FM tuning, starting a CD playing etc) but NO SOUND

I have a Parrot bluetooth and that comes through the audio system fine but I think that goes to the power amplifier?.

I suspect there is a preamplifier that is blown or shorted to ground, If faulty would I be able to get something aftermarket to replace it or am I stuck with Lexus usurious prices??

Weather here is a little cold to do evaluation so I am not in a huge hurry right now. Meanwhile if anyone could help with insight and/or wiring diagrams etc that would be really appreciated.

Thanks.