Hi, this is going to sound like a thousand posts that have come before (ie the old "my new car stereo whines.. what's wrong?! "incorrect grounding.. etc etc"), but it's not.

I just had a new stereo installed. I now have a strange whirring noise that seems to come from directly behind the a/c and temp controls. It happens when the revs go over about .. well i I don't know cos I don't have a tacho (It's an 96 Aussie CXi model), but I'd say whenever I rev high enough to need to change gears.. so probably between 2 and 5 thou?..

This sound happens without the face plate on (eg no signal to speakers etc). Now, I figured there may still be some kind of noise produced by the head unit (e.g. to do with wiring... clutching at straws here), so I diconnected the positive terminal from the battery to the stereo setup. So now I think I can safely say that if the sound happens, it's not made by the stereo right?

Well, I still get the sound. The fact that the sound originates from behind the dash instead of any of the speakers makes me suspect the audio install guy has given something a knock.. or possibly not connected up something properly..

Do you guys know what this sound might be? What A/C connections (or anything else ) are there behind the dash that could make a buzzing sound that is very obviously dependant on engine speed?

Everything sounds fine from the engine bay (have had others listen too, just to check).

Thanks in advance.

 

Have now also checked the hole in the firewall through which the power comes. The grommet was pretty shabbily done, so replaced it with a tighter one. No difference. Also plugged up completely with blue tac just to be sure. No difference.
Still searching..