JBL GTS300 Owner's Manual page 13

Power On light is blinking,
indicating a fault condition,
and sound is intermittent or
off
Alternator whine through
the audio system with the
engine running
Bass output from speakers
too low
• Defective GTS300 or GTS600; If there is
audio signal present at the input of the
amplifier and there is no output, the
GTS300 or GTS600 may be defective.
• Incorrectly connected or shorted
speaker wires; check for shorts, frayed
wiring, damaged wiring insulation or
incorrect wiring.
• The speaker combination connected to
the amplifier is less than the minimum
requirement; reconfigure speaker
connection after consulting with section
3.1 "Speaker Requirements."
• Amplifier is damaged; consult your JBL
Dealer.
• Ground loops; verify that the chassis
grounding point you have chosen is
true ground by checking for continuity
between the chassis ground point and
battery ground.
• Speaker wired out of phase; check for
proper polarity on all speaker wiring (+
amp terminal to + speaker terminal and
– amp terminal to – speaker terminal).
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