Amping Door Speakers

[Mageeunit1]

Right now my crossover is being powerd by my head unit. I wanted to amp my door speakers. (amp is already installed and is powering my subs.) I ram wire from my amp to my crossover input. after doing so my speakers stopped playing sound from them? what could be going wrong?

 

[americanaudiophile]

To be clear previously you had the speaker out of the head unit driving the passive crossover on the door speakers. You also had the RCA pre or sub out connected to the sub amp and then the subs.
If you don't have an active crossover before both amps then you would use the head unit preamp out to your new amps input (you might have to split this output to drive both the door and sub amps.) The door amp speaker out would go to the crossover and the crossover to the door speakers.