Scion makes a line of vehicles that have been widely embraced by aftermarket custom enthusiasts all over the world. One of the first options of those who seek a custom vehicle is an upgrade to the stereo system. Amplifiers provide a more complete audio experience, including increased volume and deeper bass. You can have a technician at an aftermarket retailer install an amplifier to your Pioneer stereo, or you can add an amplifier to your Scion yourself and save the cost of labor.
Disconnect the negative battery cable (or grounding cable) from the Scion's battery. The grounding cable is the black cable that connects the battery to the frame of the vehicle. Use a Phillips-head screwdriver to loosen the bolt holding the cable's clamp around the negative lead post of the Scion battery. Remove the clamp from the lead post.
Pull the air-conditioning control knobs from the dash of the Scion. Remove the three screws beneath the knobs with a Phillips-head screwdriver.
Push the air-conditioning vents downward. Grab the panel enclosing the climate control and Pioneer stereo unit and pull outward. The panels concealing the stereo will now be removed.
Remove the four screws (two on each side, arranged vertically) with a Phillips-head screwdriver.
Pull the Pioneer deck forward, away from the dash. The stereo will still be connected to the Scion. Pull far enough to reach the connecting wires in the back of the receiver.
Pull each of the wiring groups from the stereo. The three groups of wires are for the antenna, the speakers, and the power supply. Connect the wiring groups to a wiring harness adapter. Connect the free adapter leads to the stereo unit. Connect the signal cable and turn-on lead from the amplifier wiring kit to the corresponding leads of the wiring harness adapter. The proper connection can be made by matching the color coded pattern of the wiring harness adapter with that of the wiring kit.
Connect the ring terminal from the amplifier wiring kit to the positive lead of the Scion's battery. Make sure that the fuse is not seated in the ring terminal until the installation is complete. Run the wiring from the ring terminal to the trunk of the Scion. If a path has not already been established from the engine compartment to the cabin, drill a hole through the firewall. Place a rubber grommet in the hole to protect the wiring.
Place the amplifier in the trunk of the Scion. Use spacers to provide relief from the floor for ventilation.
Connect speaker wires from the amplifier to the speakers of the Scion. Use the path already established by the speaker wires from the Pioneer stereo to the rear speakers. Remove the panels securing the carpeting to the floor of the Scion with a trim panel tool. The panels can be replaced by hand.
Run the turn-on lead and signal cables (from the amplifier wiring kit) on the opposite side of the Scion as the power supply cable. The power supply will cause interference in the signal cable if laid along the same path. Connect the turn-on lead and signal cables to the Pioneer stereo (via the wiring harness adapter) and the amplifier at the other end.
Replace the Pioneer receiver in the dash of the Scion.
Reconnect the grounding cable to the negative lead post of the battery. Place the cable's clamp around the negative lead post. Use a Phillips-head screwdriver to tighten the clamp's bolt. The clamp needs to be tightened only enough so that the clamp cannot be moved around the lead post by hand.
Place the fuse into the fuse slot on the amplifier wiring kit ring terminal.
