Both front door speakers and the driver rear left speaker went out. Seems like the other rear door speaker kicks on and off. I tried replacing the other rear speaker with a brand new one but no dice. Then turned my attention to the front ones. consulting the wiring diagram I can see that the front speakers and pillar mount tweeters are on the same line direct from the radio. My tweeters were still working, so I replaced both front door speakers and they are working fine.

As you can see the rear speakers run through a component called the aux audio / hvac control, so I am working on getting to that and seeing if maybe there is a bad connection or short. Here is a link to the electrical schematic. good luck