2002 vw jetta w/o monsoon amp

I have a 2002 VW Jetta w/ a 4" radio w/o an amp under the passenger rear deck. I assume that this mean I do not have a monsoon system. My current radio will only play a really low volumes. When I turn it up the sound stops and the radio still fuctions (lights,display)

Is there a factory amp other than a monsoon?
Where is it, If it exist?
Can I fix my problem w/ an aftermarket Alpine,Kenwood etc?

How much power is coming from the factory radio (15w x2 etc.)
Will I need to purchase a crossover?

Suggestions on a fix (not a radio)

Thanks in advance

Try balancing and fading the radio to one speaker at a time.  Play each speaker individually, if it does not play loud on one speaker but it plays loud on the others, the one that does not play loud may have a problem.

I have a 01 jetta that had a factory monsoon system in it. The amp was right were yours is so im assuming you do have a monsoon system. I replaced the stock radio with a dd tv and the factory amp burnt out. Had to have each individual speaker rewired to the d.d.'s amp. Im pretty sure replacing the radio will get rid of the problem, but I wouldnt have the speakers wired to the factory amplifier.

I am trying to figure out if the VW factory stereo w/o the monsoon amp option has an amplifier or not or does it run off of the factory radio. If it does it is not in the same location of the monsoon(AcDelco)P.O.S

pull the radio out and test the speaker form the back of the radio (with the car off) you can use a tone generator or a 9v battery if a tone generator is not availiable if you get a pop from there you do not have a factory amp if you do not get any sound from popping the speakers from the back of the radio you have an amp.

Only Monsoon has an amp and it's like you said under the passenger side of the rear deck in the trunk, plus they say Monsoon on the tape slot on the head unit.