Nissan Pathfinder 1996 has no sound

[chinhminhdo]

I have factory audio system (no Bose) in my PathFinder 1996 XE, it has no sound for the front and rear speakers. The only sound I have is the mini/tweeters at the frame next to the windshield glass. I sometimes had the sounds come from the front and rears speakers until they are completely dead.

Because the factory CD player is too old, I thought it might be the problem with the CD player and replaced the CD player. However, after I installed the new CD player, I have no sound at all (even no sound comes from the mini tweeters). I don't think I have the factory amp in my stock sterero (I looked underneatht the driver and passenger seats and see no amp there).

Would someone please help me to trouble shoot this problem? Is there any wire that could be shorted and cause this problem?

Thanks

[NissanTech]

Since the same output wires that powers the front speakers, also power the twitters you may have a problem with the speakers itself. (See diagram 1)

The amp is on the luggage room and not under the seat. (see diagram 2)