My ml 320 2002 radio says no cd player installed and the radio is on but no sound is coming from the speakers...it was working fine yesterday. Is there anyone that can help me?

Unscrew the suspected speaker and use a DVOM to check that values are correct or???......Check for juice at the + terminal of speaker with radio on,probably a open circuit,check your grounds....It is possible the output is completely fried;will appear that everything is okay,but no output......

So everything is coming on but you have no sound from anything?If that is the case you may want to check the amp fuse.The car has a factory amp i'm trying to remember i think it is in the trunk.Look in your owners manuel for the fuse box location.If the fuse is good then the factory amp may be bad.Or you may have a blown speaker that is showing a short and putting the amp into protect.If the amp and or speakers are bad i highly recommend just buying after market speakers/amp.The price for the factory equipment is very high and there labor rates even higher lol.Plus if properly installed you will noticed better sound from the after market stuff as long as you get brand name equipment.Go to a well trusted audio shop in your area they should be able to see if it is a speaker or amp problem if your fuses are all good.They should be able to test the impedance of the speakers at the amp for you and see what is going on.

have you had any speakers or bass boosters installed in your car that werent in the vehicle before you purchased. Watch for wiring issues or possibly even battery voltage issues.

try resetting the cd player in cargo compartment. you may have to loosen the screws holding the cd player in place to access the plug connector on the cd player. Most likely though it sounds like the fiber optic ring is down. which could be caused by any of the audio components. e.g. comand unit (radio), cd player, sound amp, tele-aid, navigation processor.

check your wiring, make sure its not grounded behind the dash somewhere

It sounds like the amp is not functioning on the radio. If you install and after market cd player the radio still won't play because it's the same amp.

Now, if you would change the radio and it still won't play, it sound like it would be the wiring to the speakers. Speakers usually don't burn out, but anything is possible.

I hope this helped.

the cd player is bad and you can hook up subs through a rca hook up that you can hook to your speaker wires in the trunk the adapter is like 20 bucks at radio shack or local sound installer or buy an after market cd player cause yours will never work again and run rca's off the back of the radio to your trunk

check the wirings of your speakers and then check the settings on your radio.

I’m happy to assist further over the phone at https://www.6ya.com/expert/ramy_d9e7ebea3891f482

Have you check the mute mode, maybe it is in mute mode.

if you have installed a new cd player in there then the propblem could be that your speaker wires and either touching each other or grounding them selfs out.. pull of the cd player and check to make sure all the speaker wires are covered properly and no bare wires are exposed.. if you still have a factory cd player in it then you will probably need to take it to a dealership to have it checked out..