JL Audio NexD XD500/3 Owner's Manual page 12

status led / Protection circuitrY
There is a single multi-color LED on the top
surface of the amplifier to indicate the amplifier's
operating status.
1) Flashing Green: amplifier is powering up,
audio output is muted.
2) Constant Green: amplifier is on and
functioning normally, audio output is active.
3) Constant Red: Indicates that the amplifier has
exceeded its safe operating temperature, putting
the amplifier into a self-protection mode, which
reduces the peak power output of the amplifier.
When its temperature returns to a safe level, the
red light will return to green and the amplifier
will return to full-power operating mode.
4) Constant Amber (yellow): Indicates that
an over-current condition has occurred and
is accompanied by a muting of the affected
channel(s). Because the muting behavior may be
very short in duration, it may manifest itself as
an audible, repetitive ticking noise in the output.
Over-current conditions can be caused by a
speaker impedance lower than the optimum load
impedance range for the amplifier or a short-
circuit in the speaker wiring. The latter can result
from a short circuit between the positive and
negative speaker wires or between either speaker
wire and the vehicle chassis. The "Status LED"
will remain amber for a few seconds, even if the
over-current condition is of a very short duration.
This functionality can be used to diagnose a
short-circuit by only connecting one channel at
a time. The "Status LED" will turn amber when
you connect the channel that is experiencing the
problem and turn the volume up.
12 | JL Audio - XD500/3 Owner's Manual
5) LED off / Amplifier Shuts Off Unexpectedly
The only condition that will shut down
an undamaged XD500/3 completely is if battery
voltage or remote turn-on voltage drops below
10 volts. The "Status LED" will turn off when
this occurs. The amplifier will turn back on
when voltage climbs back above 11 volts. If this
is happening in your system, have your charging
system and power wiring inspected.
For more information on troubleshooting this
amplifier, refer to Appendix D (pages 16, 17).