Amp burned out

FORGOT TO SAY FUSE IGN BLOWS?
NO FUSE NUMBER TOLD FAILING. IF IS.
BLOWN FUSE, BE REAL CLEAR WHICH ONE BLEW.

22RE ENGINE,. LEARN WHAT IS THERE FIRST. REAL NAMES GET REAL ANSWERS .
22RE
ING FUSE AND EFI FUSE.
OR ENGINE FUSE. REAL NAMES SEEN USA SPEC CAR PU.
FED OR CALIF. CAR?

IGN FUSE , RUNS THESE THINGS, THAT CAN SHORT.
ALL ARE BLACK/YELLOW WIRES
FED CAR.
ECM PIN 3.
AIR INJECTOR VALVE.
EVAP VALVE
FUEL CUT SOLENOID AT CARB IN FACT 2 OF THEM.
OOPS CALIFORNIA CAR LOTS MORE;.
TOP CAUSE IS BAR NONE


TOP CAUSE SEE ?
IS SHORTED OUT O2 SENSOR, OR WIRES TO IT MELTED TO 2000 F DEGREE EXHAUST MANIFOLD. SMOKEN OUT BURNED.
OR THE 02 SENSOR IS SHORTED, AS THEY LOVE TO DO;.
JUST UNPLUG 02 SEE IF FUSE IGN HOLDS, KEEP WIRES SAFE.
NOT DANGLING.

CALIF HORROR.

You have possibly melted a couple of wires together along the radio circuit. Also the radio unit itself has 1 or more protection fuses actually inside the unit that have blown, usually at back of unit in little bay near the wire clusters.
Check your relays too, a blow out through jump starting can do all sorts of little burn-outs.

1. Stop going to this shop.
A fuse that keeps blowing is a sign of a problem. You never replace a fuse with one of a higher amperage because the idea is the fuse is suppose to blow before the the wires melt and catch on fire. The reason it stopped working and the fuse didn't blow is probably be cause the wire did melt someplace and you are lucky the car didn't burn. If it did burn and the insurance company found the 40 amp fuse, they would probably have refused to pay.
The idea that a repair shop would do this tells me that they don't know what they are doing. Read this
FUSES

Yes very much So.

there is a short somewhere.i had that problem.there were some wires melted together.

I’m happy to help further over the phone at https://www.6ya.com/expert/kenneth_3efc1f8510674f04

Check the wiring behind it. If the insulation is cracked and a bare wire is touching metal, it can cause it to ground out which will result in what you see. Likewise, if there was a short in the wiring and the casings melted together (multiple wires touching), it will do this.

the voice coils could be damaged, check for burns on the connections

at least you know were to start,key on the fuse that blew.and everything controlled by it.i'm assuming that every time you replace the fuse now,it blows .think back before the short,was there any electricial problems,or devices that didnt work.,wires are melted together,or motors are shorted out.putting a bigger fuse in probably burnt a wire open(meaning got too hot and broke)whatever blew the fuse to start with,is most likley where the meltdown is ,start unplugging the things on that fuse,one at a time,remove tail lightbulbs,inspect thre sockets,look up under the dash at the wiring ,your clock,tach.and gas gauge ,are there,observation is almost 90%of trouble shooting anything .fixing it is easy pop the hood spend some time just looking at every thing follow wires make sure they arent melted together ,and are plugged in,just unplugging something and plugging it back in will show problems,things will fall apart.clips will break and hopefully you will see something obvious,shorts are never fun,do you have any electrical background?and know how to use a multimeter .if you do reply ,

If the connections are correct...?
then it doesn't sound like theres a problem with the amp.

make sure the amp is not to powerful for the sub?
eg: 1000w amp, 500w sub.

Sounds stupid but it happens.

make sure the gain / volume is not too high!

if your BMW has a totally sealed, metal boot area this doesn't help.