Why is there no sound after replacing my car stereo?

If the new stereo switches on but all or some of the speakers are silent, this may be because the car’s factory amplifier is not being activated or is not receiving the correct audio signal.

Factory amplifiers are fitted in certain models and audio packages from manufacturers including Audi, Volvo and Saab. In some Audi models, the factory amplifier drives the rear speakers. In that case, the front speakers may work while the rear speakers remain silent.

Do I have the correct adapter harness?

Check that you use a vehicle-specific adapter harness designed for the car’s factory amplifier.

The harness needs to match the car model, model year and factory sound system. A standard ISO harness is not always enough to retain the factory amplifier’s function.

Is the factory amplifier receiving a turn-on signal?

Some adapter harnesses require a separate remote wire to be connected to the new stereo. This provides a control signal that activates the factory amplifier.

The wire is often blue or blue/white, and the stereo’s output may be labelled P.CONT, AMP REMOTE or Remote Turn-on, for example.

Connect it according to the stereo’s and adapter harness’s installation instructions. Identify the wire by its function and labelling, not just its colour.

Some installations use pin A5 in the ISO connector, but only when the manual specifies this as the correct connection for amplifier control.

Is the audio signal connected correctly?

Some adapter harnesses use RCA/line-level connections to transfer audio to the factory amplifier. In that case, the RCA connectors must be connected to the stereo outputs specified in the adapter harness’s manual.

Other solutions handle the audio signal and activation differently and do not need the same connections. Always follow the instructions for your particular adapter harness.

What should I do if there is still no sound?

Contact us with the car model, model year, factory sound system, new stereo model and the adapter harness you use. Also tell us whether all speakers are silent or only the rear speakers, and we will help you troubleshoot further.