Precision Power DCX 300.4 - Manual (Page 8)

WIRING
Before beginning, disconnect the negative (-) terminal of the battery
prior to connecting the amplifier to the positive (+) 12V terminal to
prevent a short to ground and potential damage to wiring and
equipment. Some vehicle radios have an anti-theft feature where
when the radio is removed from 12V the radio will no longer function
and must be code reset.
Note: The cables running from the battery to the rear of the car
should be installed on the side of the car opposite to the antenna.
When using 16 gauge wire or larger, run the speaker wires from the
amplifier location through the vehicle to the speakers. Observe the
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