Most Of the Aftermarket Head Unit Radio get the Sound via Factory AUX port like Mazda BMW GMC Chevy Honda.
The sound stil output the factory speakers and ampllifier. AUX just get the sound in your car.

The one of the customer feedback to us:

I recently changed vehicles, from 2017 gmc sierra to 2015 chevy silverado, can't get sound to work, everything else works , plugged in auxiliary, still doesn't work. Do I need to set truck radio to certain station? or do i have to change a setting in the radio i got from Belsee? THANKS

Solution: Need to plug in aux cable for sound.

Use the Aux input on original infotainment. And in order to physically had to plug a 3.5 aux cord into the Aux port in order to select the Aux source.

Finally: Hello: Sorry for all the trouble, My Aux. plugin was bad, got fixed, now radio works.


Other customers:


I have installed the new unit but I am not getting any sound at all.
Even on AUX there is no sound. I ran a 3. 5mm plug to RCA cable from the factory AUX port into the harness. See photos.

Finally:


I figured it out. My son asked me if the cable from the AUX to the head unit was new or if it was an old one I had from a previous build. It was and old one I had laying around. I went and brought a new cable 3.5mm to 2 x RCA and it now works perfectly!!

Sound fixed 100% the cable I used first must have been faulty.

　

The volvo head unit screen customer:

Volume knob doesnt show volume. Sound does not play. Amp is turned on in the settings

Finally: I went into car settings and sellected aux channel and it workes.