I have a 1999 Grand Prix that doesn't appear to have the Bose or Monsoon stereo. The factory CD/radio says Delco on the nameplate. When I purchased the car, only one speaker had audio coming out of it (the front drivers speaker), however every so often at least one of the rear speakers (maybe more) starts to work, but eventually stops after the car is shut off and restarted. Does this car have a factory amp anywhere and if so, where is it? Also, how many speakers doesn't this car have? I noticed there are tweeters and mid ranges mounted in the doors and possibly two 6x9 speakers in the rear deck, six total speakers, is that correct? Are there factory HPFs or crossovers?

Thanks in advance.