Anyone Know About Car Sound Systems...Passenger Side All Highs, Drivers Side All Low Bass?

Hey everyone,

I just got a new system in my car today and when I was driving home I noticed that the drivers side speakers did not seem to be working. When I got home I started messing with the EQ and faded everything over to the passenger side and it was all highs, Then when I moved the fader all to the drivers side it was all low bass. Why is it not even? What is my problem and how do I fix it? This is my first time posting here I have heard nothing but good things and my friends say you guys could help. I thank you in advance for any information you can give me and I hope to hear from you soon.