I got New speakers a while ago and i was somehow able to wire them without buying new harnesses and just using the oem wires. Anyways they had stopped working and i eventually bought the correct wiring harness for it to connect and now my front speakers no longer work. I have not a clue about car wiring

 

There are a couple of ways to troubleshoot your problem.
If you have a known working spare speaker connect that to the harness where your aftermarket speaker was connected. Sometimes the harness adapters don't work due to bad connections. If that's a no go try connecting from the factory wiring to your speaker.

Second try your head unit fader. Adjust it all the way to the front. If you hear very low sound then you have a bad head unit. Not too technical but it will lead you in the right direction. Good luck!