ML320 2003-FM radio not working except by turning the volume to maximum and it can only be heard faintly. The AM, cassette, Cd and phone work fine at normal volume. Any ideas??

Have you checked your amplifier?

Do you have base or up;level system ?

Table 1: Radio Features
Table 2: Cassette Features
Table 3: Compact Disc Features
Table 4: XM Advisory Messages
The radio receives power from the RADIO fuse in the junction block-right I/P. Ground is provided via G201 and G202. The radio is enabled/disabled by class 2 messages from the body control module (BCM). The radio routes audio signals from the digital radio receiver or the vehicle communication interface module (VCIM) to the speakers and/or amplifier when directed by class 2 messages.
The Entertainment System on this vehicle is configured with an AM/FM stereo radio with the radio data system (RDS) and either a cassette player or a CD player or both. CD and cassette. The uplevel system provides the customer with extended range speakers and an audio amplifier. Satellite digital radio (U2K) is available with uplevel systems.
The following list shows the radios available for this vehicle:
• Radio (ULO) - AM/FM Stereo, Cassette with RDS
• Radio (UNO) - AM/FM Stereo, CD and RDS
• Radio (UPO) - AM/FM Stereo, Cassette with CD and RDS .The complexity of the radio systems on these vehicle is mind blowing .

Your best bet take it to a GM dealer , has features you are unawear of .
DTC B1025, B1035, B1045, or B1055
When the radio is powered up, the radio supplies low level audio signals to the speakers. If the vehicle is equipped with an audio amplifier, the amplifier will boost the signal sent to the speakers.
DTC B1025 Audio Output Circuit
Install a scan tool.
Turn ON the ignition, with the engine OFF.
With the scan tool, monitor the DTC Information for DTC B1025.
Does the scan tool indicate that DTC B1025 is current?

Radios naturally come with am, so it will always work so long as there's power to the radio. Fm, however, is a built in receiver and if they break or start to break, then you will lose power to your fm which it sounds like is starting to happen to you.

reset radio or replace

No it doesn't. The head unit is faulty and requires repair/replacement.

usually a problem inside the radio

i was wondering if you were able to find a solution for this. I am currently having this same problem with my vehicle (as a few others as well). if you could please let me know, id greatly appreciate it. my email is [email protected].

Get some contact cleaner spray turn power off . And spray the knobs and the push buttons. Then keep pushing an turning the buttons an knobs .Let sit 30 min an blow them out with can air.Turn on see what happens. Some times you my have to do it 2 times. Are Spary and let sit overnight. Ford an Mercury's are bad to get moister in them. It worked for me a lot.

were the lights working before?
sounds like a defective radio.

You should reboot the system, sometimes these cars hicup so to speak.
Disconnect the battery, both sides, then with it still disconnected turn the key to crank 3-4 times (with the battery disconnected, this just discharges all the ecu's and clears any held memorys)
Reconnect the battery (pos + first)
After that you need to relearn the windows, with the key on or the car running send the windows all the way up, then one at a time, hold the button to bring 1 down and continue to hold for 5 seconds once it is all the way down, do the same for the up position, repeat on the other side and you should be good to go.
JPTCAT