Hi.
I don't suppose anyone can help but I thought I'd give this a try anyway. I have a Mk3 Gti which, when I bought it had the fairly standard Sony head unit with multi disk changer in the boot. The radio sounded a bit naff and non pre-recorded disks skipped, so I decided to get a new head unit. The one I opted for was the Pioneer 7400MP (MP3 etc etc). Disks now sound about as good as their going to get (as I'm still using the factory fitted VW speakers) but the radio sounded even worst! I took it along to my local audio dealer and they said it was the aerial. Apparently the 'Bee Sting' variety (middle of roof) is prone to water ingress and this can cause the booster inside to rust up. Sure enough, when they temporarily plugged a new aerial in MW sounded 100% better, and FM sounded pretty good too. The following week the installed the new aerial, and a complete new lead to the head unit. I drove the car down the road fully expecting FM to be pretty near perfect, but it wasn't :-( In fact, the new head unit was mearly making whatever the problem is sound worst due I suppose to it's amplified power and better reciever. I took the car back to the audio dealer and they had it for a whole day before actually admitting defeat. Two guys, 35 years experience each, and they were completely baffled. They tried everything. The little plug in booster that looks like a cigar tube, new aerial, they earthed everything, tried another brand new head unit but all to no avail. It seems when an aerial is plugged in and held outside the car the reception is fine. Move the aerial inside the car and the reception takes a nose dive. Something in the car itself is causing the reception to weaken.
This happens all the time, whether the engine is on or off. I have pulled every fuse out of the box except the radio and it still does it. I have disconnected the front speakers, then the rear ones thinking it might be a trapped wire etc but it makes no difference.
The only thing I can now think it could be is the alarm. I'm sure the transmitters have a battery backup and this might account for why the reception was still poor after I removed all the fuses. Also I don't seem to be able to switch the alarm off. Turning the key under the bonnet seems to switch it fron on to on. The alarm works all the time! It's a logic 900 alarm immobiliser if anyone knows anything about them? Maybe if I could switch it off I'd know for sure whether it was the alarm that was causing the problem.
Anyway....if anyone has any ideas I'd be eternally grateful.
