Don't know how similar to Hifonics amps but heres some stuff they have in their manual.
Amplifier heatsink overheating
The amplifiers will shut down when the heatsink temperature reaches 80 degrees centigrade, and turn back on once the unit has cooled down below that point.
Causes of overheating:
1 - Inadequate cooling - relocate or remount to provide better natural airflow over the fins.
2 - Driving high power levels into low impedances - back off on the volume control, and/or make sure you are not loading the amplifier with less than the
recommended loudspeaker impedance.
3 - Excessive voltage drop can also cause overheating.
System does not turn on
1 - Check all fuses.
2 - Check all connections.
3 - Measure the +12 volt and remote turn on voltages at the amplifier terminals. If these are non existent or low, take voltage measurements at fuse holders,
distribution blocks, the head unit’s +12 volt and remote leads to localize the problem.
4 - If the HIFONICS lettering is illuminated but you do not have Power or Protection illuminated, simply remove your remote wire and use a jumper wire from 12V+
on the amplifier to the Remote connection on the amplifier. If the amplifier powers on like normal then you do not have adequate voltage/amperage from your Remote
source to turn your amplifier on. You will need to seek out a certified installer to install a relay for your amplifier. If the jumper does not power your amplifier on, you
may have internal damage and should contact Hifonics Customer Service to locate an Authorized Repair Center.