I've tried to read as much as I can about this particular problem, but I'm still coming up confused. So here goes...

My 2001 Quad Cab truck has the original Infinity stereo system. Both speakers in the passenger-side front door are dead (main speaker and separate tweeter). All the other speakers work fine.
From my reading, I understand there's a separate amp attached to the main speaker in the door. What I'm not clear about is if that amp serves the tweeter as well. In other words, if both speakers are dead, is the problem the amp, the speaker wiring going to the door, or something else?

Basically, I'm trying to figure out the simplest way to fix this problem before I order any parts. Do I need to replace both door speakers, only one, the amp in the door, the wiring, or the head unit in the dash?

This is one of the most confusing car stereo setups I've ever encountered. All help appreciated.

 

Check your wire in the pass through from the main body into the door. Sometimes the wires get crimped or break in that wierd little rubber tube. My dads 96 did the same thing and I found a broken wire in the pass through.
Good luck

 

If you get stuck, you can always swap the speakers between the left and right doors to see if the problem follows the speakers or not.