Garmin FUSION APOLLO RV-RA770 Installation Instructions Manual page 13

Zone 1 speakers
Water-tight connection
Zone 2 speakers
Amplifier-on signal wire
You must connect this wire to each amplifier connected to a zone line out.
A connected amplifier must use the same ground (-) as the stereo for this signal wire to function
correctly.
Powered amplifier connected to the zone 2 line out
Zone 2 line out and subwoofer out
Each subwoofer cable provides a single mono output to a powered subwoofer or subwoofer amplifier.
You may need to use an RCA splitter to connect this to an amplifier.
Subwoofer
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