I have just fitted kenwood hu to my harmon kardon system, great sound no background noise sw ok. bought wiring harness from nexxia. the first rig i got had noise so i got back to them. they asked me to try a new rig they had come up with,only problem is no steering controls, i can live with that.
remove trim from bottom of windscreen down to pollen filter housing the metal plate over housing has a screw with afibre washer which breaks down and lets water throu into pollen filter case under glovebox silicone does the job
remove trim from outside lower windscreen down to metal plate over pollen filter case the screw fixing this plate has a fibre washer which corrodes and lets water in though the pollen filter under glove box