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ElectronicsPete, Electronic Engineer
Category: Car Electronics
Satisfied Customers: 15454
Experience:  Over 16 years of experience installing and repairing electronics.
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On GMC Sierra Truck radio there is no sound or volume bar

Customer Question

I have a 2004 GMC Sierra Truck and while on my way to work my stereo worked fine, but 4 hours later I noticed I had no sound and while trying to turn up the volume, there was no volume bar showing and it wouldn't do anything but turn. I still see information on the time and musician playing along with the title of the sound, but no sound and no volume bar.
Submitted: 2 months ago.
Category: Car Electronics
Expert:  ElectronicsPete replied 2 months ago.
You will need to check for shorted speakers or speaker wires.
Perform the following checks to determine if it is a radio or an amp issue. Do these checks with vehicle running, radio on and amp plugged in:
Check for audio at the Rear Seat Audio controls through the head phones. If there is, then the radio is producing audio.
Check pin B3 (switched 12volts) for 12 volts. This is a radio output that tells the amp to turn on. It should show 12 volts, if it does not, and then radio B3 pin output is not operating properly. This could be caused if the radio is not programmed correctly or a circuit concern.
Check pin B6 (amp mute) for 0 volts to 5 volt. If the voltage is between 0 and 1 volt this tells the amp to unmute and play. If it shows between 3 and 5 volts this tells the amp to mute and stop playing. This could be caused if the radio is not programmed correctly or a circuit concern.
If the above steps indicate that the system should be playing then check for power and grounds to the amplifier and if ok, replace the amplifier.
Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.
You can always reply back at any time if you need further assistance.

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