Radio not working. On the computer dash it tells me audio low battery. What is wrong

bmw SERIES 7
12VDC POWER>?
WELL THE OBD2 PORT ,PIN 16 IS 12VDC RAW POWER AND IF DEAD ITS FUSES IS BLOWN!
OR THE CARS BATTERY IS DEAD.
BATTERY LUGS CLEAN AND TIGHT ,NO RUST.?
WHAT IS WRONG IS NOT TELLING ALL THAT WORKS AND DOES NOT IN BRIEF.

1. Y/N ENGINE RUNS. AND DRIVES.
2. HEAD LAMPS WORK KEY ON OR OFF?
3. RADIO WORKS
4. ALL EXTERNAL LAMPS WORK F/R
5. DASH HEATER BLOWER WORKS ON HIGH?
6. IP CLUSTER LAMPS ALL SEEM TO WORK NORMAL KEY ON.?
7. BRAKE LAMPS WORK AND PARK LAMPS AND TURNS, ?

ELECTRICS ON CARS ARE COMPLEX.
WHAT FAILS AND DOES NOT FAIL IS A HUGE HUGE CLUE TO DISCOVERY
AS IS CHECKING ALL FUSES FIRST.
BATTERY RESTED VOLTAGE IS 12.6VDC IF LOWER IS DISCHARGED.
IF IS LOW, JUMP CABLE JUMP START THE CAR.

Was it dieing before you replaced the alt? Did the battery voltage get too low and then you charged the battery? If so then sometimes it takes a drive or two to recalibrate the sensors to the computer. Also make sure the new alt is working. Dash lights and radio are probably fuses or bad headlight switch.

Check the float in the fuel tank (sender). If you can remove clean the contacts, these are 2 slide tracks. You can test before placing back into tank.

Audio Item Wire Color Polarity Wire Location Radio 12V red/white + radio, black 14 pin plug, pin 1 Radio Ground black/white - radio, black 14 pin plug, pin 8 Radio Ignition (low speed GMLAN) Radio Illumination yellow (dimmer) + radio, black 14 pin plug, pin 7 Left Front Speaker (+/-) dk. blue - lt. blue +,- radio, black 14 pin plug, pins 2 - 9 Right Front Speaker (+/-) orange - dk. green +,- radio, black 14 pin plug, pins 3 - 10 Left Rear Speaker (+/-) tan - white +,- radio, purple 16 pin plug, pins 5 - 13 Right Rear Speaker (+/-) tan - orange +,- radio, purple 16 pin plug, pins 6 - 14 Satellite Radio 12 Volts red/white + Digital Radio under driv dash, 16 pin plug, pin 16 Satellite Radio Ground black/white - Digital Radio under driv dash, 16 pin plug, pin 9 Satellite Radio Ignition (low speed GMLAN) Satellite Radio Antenna (coaxial cable) Satellite Audio Left (+/-) brown/white - tan/white +,- Digital Radio, 16 pin plug, pins 2 and 1 Satellite Audio Right (+/-) dk. green/white - gray +,- Digital Radio, 16 pin plug, pins 3 and 4 2016 Chevrolet Express Van Wiring

the dash has a dimmer, this is dash park lights
and runs all radio back lights.
so if the dial is low, its dark
if the dash cluster glows good the dimmer is ok
and the wire to the radio called, dial

on after market radios its the orange wire. not 12v, its dead.
http://knowledge.sonicelectronix.com/car-audio-and-video/accessories-and-installation/wiring-harness-color-standards/

suzuki uses different colors.
turn on parks, with a voltmeter measure 12vdc at DIAL wire.
at radio.
0v bad, 12v good, if 12v then radio lamps are Blown out.

Here is an example of a stupid question

A guy --- tells you with no testing-- you have a fuse problem,really!

Can you tell me the problem--NO ONE CAN

It won't start --so someone on the internet should be able
to guess at it,again with NO TESTING what so ever

Tell them what's wrong with the radio,again really,The Car Won't
Start, who cares about the radio,you can't use the car

check ignition switch

it sound like your battery cables might be a little loose alowing moisture to get in. now this includes the cable connection on the starter

Sounds like all of the high drain devices are disabled due to a weak battery. You are still getting dash lights and radio because they are very low drain devices. Try charging the battery to test for now. It could be a failing battery, or your alternator and or voltage regulator could be going out and not charging the system. But first, try to charge the battery, and see if you can start it, if you can, let it run for at least 10 minutes. If your alternator/VR is going out or is already out, you should have a guage, or idiot light telling you that you have low voltage. If its a light, you should see a red battery lit up on the dash, if its a guage, it should be directly in the middle +/- a little. If you are able to run the vehicle for a while with no light coming on, or guage showing low voltage, its safe to say you drained the battery, or it is failing. If its a few years old or more, i'd go ahead and replace it. Hope this helps :)

you have to check all fuses with a test light both fuse boxes under hood and under dash... if good next to look for is the light switch itself... has any radio work been done to the lately... if so alot of times hooked up wrong will blow park fuse as one of the wires to radio is the park voltage to tell radio to dim down some