Factory Stereo I have a 2005 altima and suddenly the speakers have stopped working. The radio still turns on and I am able to switch stations and all other functions but still no sound. Could this be a fuse problem or a wiring problem, or neither?

If you have lost control over the radio, then there is an issue with the control module and/or board. The stereo will need to be repaired/replaced.

Here you go. Be careful this can disable the truck in some models due to the radio system be tied into the factory anti theft system..

2009 Chevrolet Tahoe Stereo Wiring Diagram
Car Radio Battery Constant 12v+ Wire: Red/White
Car Radio Accessory Switched 12v+ Wire: The radio harness does not provide a switched power source. The accessory turn-on is controlled by the lan serial network. Run a wire to the fuse box or ignition switch harness.
Car Radio Ground Wire: Black
Car Radio Illumination Wire: N/A
Car Stereo Dimmer Wire: The radio harness does not provide a dimmer wire. The dimmer wire is controlled by the lan serial network.
Car Stereo Antenna Trigger Wire: The radio harness does not provide a antenna trigger wire. The antenna trigger wire is controlled by the lan serial network.
Car Stereo Amp Trigger Wire: The radio harness does not provide a amp turn on wire. The amplifier turn on is controlled by the lan serial network.
Car Stereo Amplifier Location: N/A
Car Audio Front Speakers Size: N/A
Car Audio Front Speakers Location: N/A
Left Front Speaker Positive Wire (+): Tan
Left Front Speaker Negative Wire (-): Gray
Right Front Speaker Positive Wire (+): Light Green
Right Front Speaker Negative Wire (-): Dark Green
Car Audio Rear Speakers Size: N/A
Car Audio Rear Speakers Location: N/A
Left Rear Speaker Positive Wire (+): Brown
Left Rear Speaker Negative Wire (-): Yellow
Right Rear Speaker Positive Wire (+): Dark Blue
Right Rear Speaker Negative Wire (-): Light Blue

it sounds like u didn't put the speaker connector thoroughly! Putting the stereo back might have disconnected the connection. Check it again!

is the radio connected to a relay under the hood?

1995 Nissan Altima Car Stereo Radio Wiring Diagram
Car Radio Constant 12v+ Wire: Pink
Car Radio Switched 12v+ Wire: Blue
Car Radio Ground Wire: Chassis
Car Radio Illumination Wire: Red/Blue
Car Stereo Dimmer Wire: Red/Yellow
Car Stereo Antenna Trigger: Green/White
Car Stereo Amp Trigger Wire: N/A
Car Stereo Amplifier Location: N/A
Front Speakers Size: N/A
Front Speakers Location: N/A
Left Front Speaker Positive Wire (+): Blue/White
Left Front Speaker Negative Wire (-): Blue/Yellow
Right Front Speaker Positive Wire (+): Brown
Right Front Speaker Negative Wire (-): Brown/White
Rear Speakers Size: N/A
Rear Speakers Location: N/A
Left Rear Speaker Positive Wire (+): Red
Left Rear Speaker Negative Wire (-): Green
Right Rear Speaker Positive Wire (+): Blue
Right Rear Speaker Negative Wire (-): Pink

lol...My 02 Altima Original Radio....wouldnt read ..or skipped on Cd,s in the morning ......in the evening it played fine.....I replaced it with one that plays mp3,s......and very happy now :) 6 years is the norm for a radio...

Here ya go. enjoy!
2002 GMC Sierra C1500 Car Radio Wire Color Codes
Car Radio Battery Constant 12v+ Wire: Orange
Car Radio Accessory Switched 12v+ Wire: Yellow
Car Radio Ground Wire: Black/White
Car Radio Illumination Wire: Brown
Car Stereo Dimmer Wire: Gray
Car Stereo Antenna Trigger Wire: N/A
Car Stereo Amp Trigger Wire: N/A
Car Stereo Amplifier Location: Under the center console.
Car Audio Front Speakers Size: N/A
Car Audio Front Speakers Location: N/A
Left Front Speaker Positive Wire (+): Tan
Left Front Speaker Negative Wire (-): Gray
Right Front Speaker Positive Wire (+): Light Green
Right Front Speaker Negative Wire (-): Dark Green
Car Audio Rear Speakers Size: N/A
Car Audio Rear Speakers Location: N/A
Left Rear Speaker Positive Wire (+): Brown
Left Rear Speaker Negative Wire (-): Yellow
Right Rear Speaker Positive Wire (+): Dark Blue
Right Rear Speaker Negative Wire (-): Light Blue

Try radio shack, or stereo sales/installation place for ready to go plug adapter. For a few bucks, it saves headaches, and butchering the wiring in case you want to re-install old one later when trading in or selling the car.

Sounds like the speakers are blown did you have sound there before or is this somthing that just happend. I would try a new speaker if the problem is still there check the wires for breaks.But sounds like a blown speaker also find out if there is a factory amp and if you have done any new wiring to the sterio check that aswell hope this helps.

sounds like there may be a problem with the stereo.