The first step in the process is to start with the battery and for this proper connections are required to get the best performance from the car's stereo system. The battery’s charging lead must be smaller than the amplifier’s lead. A better idea is to upgrade this to a 4-gauge power lead from the alternator to the battery so that the potential power from the alternator is not restricted.
Next you will have to run the wire through the firewall of the vehicle. Factory grommets are mostly unused in most of the cars and the best idea would be to run the wire through it. But before doing this, you must ensure that the open area in the grommet has essential space for the wire to pass through it.
Next in line is to avoid the fact of wire interference. The wire of the stereo system must not interfere with any parts or any pre-existing wires of the car’s own system. This may well get a clash with the car’s steering wheel linkage, the brake pedal, the gas pedal or the clutch pedal as all of these run from the same origin.
Now we will have to consider the amplifier location. There may be 2 possibilities. One is to install it under a seat of the car and the other alternative is to place it in the rare of the car trunk. Whatever place you have selected for the amplifier, just make sure that there’s enough space for it and its wires to get to the amplifier.
Finally, you will just have to deliver signal to the amplifier and doing this, your car’s sound system is ready to kick-off. Just check the car’s stereo settings and check for the reducing noise and the speaker polarity.