Under the passangers FEET.... (not seat)
The amp is intergrated with the speed of the vehicle and will raise in volume to compansate for road noise. The decoding or otherwise signal source is located in the trunk --drivers side--
This device is a processor which processes signals from the antenia (for radio stations) and from the CD player. The component in the dash is just a 'remote' and cassett motor. The 'High' tweeter speakers and wires to the amp for the door (midrange and woofer) come from the unit in the trunk. The wiring is all inter-connected under the carpet (UNDER THE PASSENGERS FEET ) CAUTION.... THIS IS WHERE THE AIR BAG ACTIVATOR IS AS WELL