Amplifier Interface (Non - GMLAN)

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

A 30A AMPLIFIER fuse, located in the rear BEC, provides the main amplifier power for the amplifier. The radio remote enable circuit provides a switched 12-volt output to the non-GMLAN amplifier. This output controls the power - state of the amplifier. To respond quickly to audio input and control signals, the amplifier is ON in all vehicle power modes except OFF and CRANK Request. However, when the amplifier is asleep it still must allow chime functionality. The internal amplifier bridges are fully powered and unmuted when the amplifier receives the switched 12-volt input.

The radio provides a amp control output circuit to control overall muting of the non-GMLAN amplifiers. The amplifier receives PWM signals on the circuit at varying duty cycle percentages for controlling the muted and unmuted functions of the amplifier. The radio monitors the remote amp control circuit for faults and sets the appropriate DTC when detected.

The function table below shows the four possible amplifier mute functions.

Function Table

% Duty Cycle Out	Function
0% (0Vlow Vdc)	FOUR_CHANNEL_UNMUTE
50%	REAR_MUTE (input must be 2-channel)
75%	SIX_CHANNEL_UNMUTE
100% (5V high Vdc)	ALL