OnStar Microphone Replacement
WARNING: This page is about a different car, the 2005 GMC Canyon and 2005 Chevrolet Colorado. However, it is still accessible from the selected car via links, so may be relevant.
The OnStar® microphone (1) located on the inside rearview mirror can not be serviced separately. Should the microphone need to be replaced, the entire inside rearview mirror assembly will need to be replaced. Refer to Rearview Mirror Replacement in Stationary Windows.