6
GMOS-04
1) Turn the ignition on if not already, and then turn the radio on to verify that the radio
works. Check balance and fader controls for proper operation.
2) Push the OnStar button (if equipped) to verify OnStar is working. The radio will shut off or
mute, depending if the
Brown
wire on the 16-pin harness is connected, and OnStar will
be heard through the front speakers. Turn off OnStar and the radio will turn back on.
Chime Volume Adjustment
Note:
If Y91 is present on the RPO list, refer to your owner’s manual to adjust chimes.
1) With car on, shut off car and leave keys in ignition. Open
the car door and leave it open. Chimes will be heard.
2) Wait 10 seconds, then with a small screwdriver adjust
the potentiometer fully counterclockwise (all the way left),
then clockwise to raise chime level and counterclockwise
to lower the chime level.
3) When the volume is at the desired level, remove the keys
from the ignition. This will lock the chime volume at its
current level.
Audio Level Adjustment
1) Start your vehicle and turn on the radio having audio playing.
2) Turn your aftermarket radio’s volume up ¾ of the way.
3) With a small screwdriver adjust the potentiometer clockwise to raise the audio level and
counterclockwise to lower the audio level.
4) Once at desired level your audio adjustment is complete.
OnStar Level Adjustment
To adjust the OnStar volume level find the
Black/Yellow
wire on the 16-pin harness. Push
the blue OnStar button, while the voice is speaking tap the
Black/Yellow
wire to ground.
There are 4 volume settings for OnStar; once the 4th setting is reached and the
Black/
Yellow
wire is tapped to ground it will automatically go back to the first volume setting.
Once the volume is set it will stay at that volume until the
Black/Yellow
wire is tapped to
ground again. This can be set during installation and then left alone. If user adjustment is
desired, the customer may also tap volume up or down on the steering wheel (if equipped)
to adjust the OnStar level.
Testing the GMOS-04
Potentiometer located on 16 pin
side of the interface
