GM Service Manual Online
For 1990-2009 cars only

Low Audio Output from Speakers - keywords amplifier calibration communication display error inoperative lock no program radio sound volume

Subject:Low Audio Output from Speakers

Models:2003-2006 Chevrolet All Full Size Trucks and Utilities
2003-2006 GMC All Full Size Trucks and Utilities
with RPO UQ7 without Y91



The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Condition/Concern:

Some trucks and utilities equipped with RPO UQ7 without Y91 may have low audio output from the speakers. There have been cases of the radio connector C1 getting plugged into the female end of C220, and the male end of C220 getting plugged into the radio. The male end of connectors C220 and the radio connector C1 are the same.

Recommendation/Instructions:

To help confirm that the radio C1 and C220 connectors are reversed, remove the 30 amp "Radio Amp" fuse from the UBEC. With the fuse removed turn ignition on and operate radio, if there is audio from the speakers the connectors are reversed. To correct the concern switch the connectors back to there correct location.

Note: C220 is located behind the radio/HVAC controls.

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.