My husband put a new stereo into our 2002 mercury sable and extended speaker Wires he tried to extend the passenger side no sound anymore. The radio works but now no noise from any speaker. Why?

Pinched, broken or shorted wiring.

Time for him to expose ALL of his wiring and see where he left an open connection or pinched or punctured and grounded or cut a wire. He should hook up one speaker at a time and make sure each one works as he continues to wire them all in & then leave the radio playing while he puts all the trim pieces back in place to see if anything stops working. If it does, the problem will be in the last piece of trim he puts back or last wire he tucks back into place.

I own a 2001 Mercury Sable. Months ago all of the left side stereo (speakers) went out. I did very little research on how to fix it but an online forum gave me a great place to start. In the trunk if you lift up the left side carpet and find your silver amp box you will notice that the original stock unit has three plugs attached to the unit. After tinkering around I found all I needed to do was lift the left side plug up where it connects to create contact for connection for all of my speakers to work again. I shoved a white disposable camera roll cap underneath it and it works like new again. I really hope this can help someones problem if the same things are happening. Please let me know if you have any questions or comments. Please take a look at all the photos attached and notice the white cap placement under the "top" connection.