Car Stereos: unexplained car speaker noise, monte carlo ss, seatbelt reminder

Question
I have a 2001 Chevy Monte Carlo SS that has the anti theft locking system.  Upon unlocking the door with the remote I can hear noise vibrating from the Left door speaker even though the stereo unit is off.  Can the problem be related to the theft locking system or the amplifier in the trunk causing vibration in the speaker?  It's driving me crazy!

Answer
Hi Emory,

If there's a problem in the system, I'd be more inclined to suspect the head unit, rather than the speaker or amp.  In your car, the factory head unit generates all the vehicle warning chimes and plays them through the driver's door speaker.  If you have Onstar, it's also designed to play through that speaker.

I haven't heard of a problem with the speaker output related to the factory keyless entry/alarm system.  Are the other warning chimes (ie, lights left on, door chime, seatbelt reminder) working properly?

In any case, the fact that it's coming from the driver's door speaker makes me think it's related to the warning chime system.  I doubt that the amplifier is producing the noise; I think it probably originates with the head unit.  You might try calling a dealer's service department and see if they've heard of this issue.

Good luck!

Brian