Altima speaker problem

Trying to get a 97 Altima ready for my daughter to drive. Original radio only plays out of right tweeter on dash and not loud. I put in an aftermarket radio with wiring adapters and got nothing. I did have to ground it for it to work. It comes on but no sound at all. I know the radio worked fine just before I pulled it from her old car. I now suspect the original radio was'nt bad. I find it hard to believe all the speakers are bad. My question is, I see these two boxes mounted under the rear window deck, are they amplifiers and can they be bypassed if they are bad? I pulled the connector off of one and lost the sound in the one tweeter with the old radio.Any suggestions would help. Thanks.

not familiar with Altimas, might wanna ask the Nissan guys

It's quite possible you don't have the radio's remote lead wired to the harness to turn the amps on.

Well, as it turned out, all the speakers were blown. What are the odds? Thanks for the input.

odds are pretty high actually. They are like $5 speakers.