Phase 1 Installation
- Factory Head unit or aftermarket head unit.
- Factory speaker wiring.
These diagrams are specifically aimed at a simple factory replacement/upgrade that will not require additional wiring or stereo system upgrades. The OPTIONAL resistor allows wiring multiple 4 Ohm speakers in parallel by adding 2 ohms back to the reduced impedance and will keep your factory stereo safe. When you decide to upgrade to an aftermarket amplifier simply remove the resistor to produce the 2 ohm impedance the amplifier wants.