Circuit/System Description

WARNING: This page is about a different car, the 2008 Cadillac SRX. However, it is still accessible from the selected car via links, so may be relevant.

The up-level radio (UQA) supplies 4 channels of audio to an amplifier. The amplifier supplies 10 input signal channels to 11 speakers. Each audio output channel circuit (+) and (-) at the radio and amplifier if equipped, have a DC bias voltage that is one half of the battery voltage. The audio output channel circuits will measure approximately 6.5 volts DC when using a DMM. The audio music or talking being played on the audio system is produced by a varying AC voltage that is centered around the DC bias voltage on the same circuit. The AC voltage measured on these circuits on the output of a radio that is not amplified will be approximately 1-3 volts AC when using a DMM. The AC voltage is what causes the speaker cones to move and produce sound. This voltage will vary depending on what type of audio is being listened to, talk or music, and type of music, and the volume setting of the system. Low volume and talk settings will measure around 1 volt AC and less, where constant music may measure 3 volts AC and slightly higher. In an amplified audio system, these similar AC voltage measurements may be slightly higher on the output of the amplifier, and the typical AC voltage readings at the output of the radio are less than 1 volt AC.