Help its aggrovating!!!

Have you checked so see if your power cable is the right size?? Is it a 220 or 110? If it is 110 then it will cut off after it gets hot, if it is 220 and the power cord is too small then the machine will be trying to pull more amps than the cord can handle causing it to overheat and shut off.. My husband has been a welder for 20 years.. I'm just passing along what he suggested might be the problem.. Hope this helps!

Defrost is turning the fans on so there is probably an issue with the fan controls on the car.

they have a built in overload thermo cut out when it is on for a long time it will cut out cool down and should be ok to use again

Perhaps this is a safety mechanism in your car. Once it gets to a certain temperature, it shuts itself off. There are alot of cars out there that once they overheat, and turn the car back on, it won't turn over.

check the cooling fans inside the amp i suspect that they are not working properly and this causing it to overheat which will shut it down via a thermistor to prevent damage

If it runs after a cool down period, then the high temperature limit is part of the cause. What is causing the high temperature limit to overheat is next.
Strong stream of air should be felt coming out the exhaust, make sure this exhaust air works or the burner part will overheat and cut out the flame/burner on hight temp safety.
With good exhaust air varified, the drying air operating temperature sensor needs to be checked, this cuts power to the burner. The sensor must open electricaly when satisified on temperature and should be properly mounted for proper sensing of temperature.
Bottom line: Check the hot air and its control

if when your bike gets to riding temp. and, you turn it off; and, then restart... if the crank speed is slow replace your battery if your crank speed is normal replace your ignition module (batteries can be recharged and, measure 12 volts and, still be weak)
Amps can fall off (amps are what give the battery muscle to spin your starter ) ignition modules can be affected by heat and fail to maintain spark

your amp may be overheating, or you have it up too loud and the surge protector is shutting it of in fear of damage to your amp.

that amp cutting out like that means that its probably shot and it time to start looking for a new one

It shuts off because the remote turn-on wire to the amplifier is connected to the power antenna wire behind your head unit. The power antenna wire is only activated when the tuner is selected. You need to switch the remote wire to the blue/white wire from the head unit (currently you're using the blue wire). This is the true remote output, and will activate the amp whenever the head unit is powered on.