On a 2007 Denali with a OEM GM CD player unit, we took out the CD player unit and installed a OEM GM navigation unit, part#25797978. After the install, everything works fine (nav,radio,cd), with the exception of the volume. The volume is pretty loud and will not respond to the steering wheel volume control or the volume **** on the nav unit.

The steering wheel volume worked fine before, so I know there is nothing wrong with the steering wheel. Could it be a locked volume setting on the nav unit or even a loose connection?

What could be the problem?

Thanks in advance for your help...

 

help!

 

The unit needs to be reprogrammed for the vehicle it is in.