If i hooked up all my aftermarket stereo wires to the maching wire. the stereo turns on but no sound comes out what should i do?

In many cases following wire colours is fairly safe but aftermarket stereos don't seem to conform to any particular colour code so in order to avoid an unintended short circuit it is necessary to positively identify the function of each wire/pair of wires.

My advice is to start again, get it right this time and hope you haven't damaged the unit.

You can find the wiring diagram for your BMW on newtis.info website. Use that to solve the speaker wiring problem.

It sounds like your amp isn't shutting off. If its humming when the stereo is off, and the key is in the off position, make sure that you have the remote power wire coming off the amp hooked to the blue/white wire coming off the stereo harness(with aftermarket harness). If your using the stock stereo, it can be hooked to the switched 12+ wire ( lookup factory wiring here:
The Install Doctor The Do It Yourself Car Stereo Installation Resource... ) but the amp will only shut off with the key off, not when the stereo is off and the key is in the on position.

I need to have more info about how you installed it, did you use rca wires from the radio to the amp.? Make sure the sub setting on radio is turned on. Make sure rca wire are in the input connection and not output, also check you connection from radio that they're in rite place. I really need more info about the map of your wireing

Did the truck have the premium sound system? If so, you will need to connect the blue remote wire to the blue remote wire on the harness. You may also need a special harness to bypass the factory amplifier.

Most Bose car stereos have an external amplifier. You will need to see if that is the case on your factory setup and remove the amplifier. Then hook the new headunit straight to the speakers.

If you bought a wiring adapter kit for the aftermarket stereo, the unit should hook up directly to the stock bose system. Note: If there is sound coming from the speakers after installation, the amp IS hooked up...the speaker wiring is routed to the factory amplifier, not the stereo itself, the stereo wiring is just signal leads to the amplifier. In some instances, you may have to connect the amp remote wire to the remote wire coming from the aftermarket stereo(blue wire). I hope this helps. Any other questions, just reply.

There should be a wire in the factory harness that turns on the infinity amps. If you used an aftermarket adaptor harness it should have a blue or a blue white wire in it, or both. When this wire, or wires receive 12V, the factory amp will turn on. this will need to be hooked to the aftermarket stereos blue wire.

If you still haven't fixed this, look at your wiring harness. The blue wire that comes off your factory harness is the external amp in the Infinity stereo. I found this out when I hooked my Pioneer head unit up. Coming off the aftermarket stereo should be a blue wire that says remote. Hook those up and you should be good to go.

You may be connecting this stereo into an amplified system. If the original factory stereo worked with the factory amplifier, your stereo is not turning the amplifier on. If you purchased the aftermarket wire harness that mates to the factory stereo connector, hook up the "Amplifier Trigger" wire, this wire is usually blue.