Car Head Unit

I just got a new cd player and i was going to put it in myself and i bought the scosche harnesses to go with it and when i spliced the harnesses to the harness with the cd player and pluged them in, i get power and all but no sound what so ever. I went over my speaker connections and they were all correct and all. Can anyone tell me what might be the problem, maybe someone has put one in before or someone came over the same problem.

I appreciate any help
thank you