I have a Garmin Nuvi885T and all of a sudden it stopped making any sounds at all and does not respond to spoken commands, even though the little green icon appears in the corner of the screen when I push the button. The map and GPS features still work fine, but it won’t talk or listen to me. I did nothing to the unit between the time it talked and when it stopped. It was working fine when I shut the car off and let the unit shut itself off. The next time I started the car and the Nuvi up. It was silent. I checked the volume and it was at 100 percent and mute was off and internal speaker was selected. Why does my Garmin Nuvi 885T suddenly go mute? What can I do to fix it? Please advice. Thanks.