After I installed a MTX 4 channel amp under the driver seat and replace the rear 6x9" speakers, I heard the strange high pitch 'weeee' sound inside the cabin. It gradually increase when the revs starts going up and disappears when the car stops.
The sound is still there even I turned off the stereo so it is not from the speakers. Is that some sort of circuitry or electrical problem?
Also after they took the interior apart (including the airbag plugs) for the installation, the air bag light on the dash comes on when I start my car, did they screw up the connections or is merely a precautious measure everytime someone tampered with the airbag connection, which need to take back to the servicing for resetting?
Would any electrical enthusiasts out there give me some answer just to ease my mind before I take back to the servicing?
