Radio no sound, amp location and wiring diagram needed

The 2002 didn't come from the factory with an amplifier, just a simple head unit and either 2 or 4 speakers depending on the option package. Attached is the OE diagram. As the new unit turns on I would look at the wiring that came with it and test each of the speaker outputs at the back of the radio and see if it is putting out any audio.

Yes, but even that didn't use an external amplifier. It used one internal to the radio. The common units looked like the attached images. Is yours one of those? If not, take a picture of the unit and the connectors, there were a a few other units that would fit in the dash but were not the factory installed ones.