car stereo....

hello all ... i just had to write cuz i dont know how to go any further... i took off my radio cuz sound came out sometimes and got dead once in a while .. so i got tired of it i thought i would get my CD player with Mini Disc... its a separate version..
CD has the amp and radio and MD has EQ.. I always believed this..
THEN after i installed ONLY the CD (cuz fleetwood 83 can only fit one where the old radio was)sound is there but its barely heard... aaaaaaa its not loud at all...
it says 35wattx4... so something must be wrong.... what can i do ?? where can i check?? tomorrow just incase i would try it with my MD... maybe the amp works only with MD?? cant be but i would just try.... please if you know what i should do help me... i dont want to drive with NO sound....