The tweeters are spliced into the front doors speaker wiring before that wiring goes through the door pillar. If the tweeters still work, then I would think your problem is where the harness passes through the pillar.
(OR. Start checking wiring after the tweeters)

 

Nope, the tweeters are wired in series with the front doors.

I know the diagrams are posted at least 20 times. I don't feel like doing it again.

 

Hmm. Either I've got the wrong schematic (2006 radio w/o amp) or I'm looking at it wrong.

 

That's what I call series, maybe it's really parallell, I was agreeing with you. Most people think they are either wired separately or there is a cross over at the doors (I guess a cross over would make it series).

 

It’s an inboard connection , away from rain and corrosion, so they will still work.

 

Well I wanted to report that I seem to have fixed the issue. It's been playing for almost 3 days without any issues. Which is longer than it's played since I've owned it without any sound loss. The problem is I don't know how I fixed it. I just pulled all 4 door panels and the aftermarket pioneer speakers. Unplugged the speakers and harnesses and inspected the door wires as far up as I could see. Then I carefully routed the wires away from everything and reassembled all the doors panels and speakers. I didn't see anything glaring or odd to speak of in the doors. Then I pulled the radio out of the dash and did the same. Unplugged everything and made sure to route the wires and zip tie nicely and reassembled the radio in the dash. After all that and feeling like I didn't find or fix anything...it was nice to find I must've done something...because it's working great. all I can assume is all the wires I moved around, I must've moved them just right and caused whatever was shorting to stop all that nonsense ...anyways thanks for y'all's help

 

So long as it works! Now CRANK IT UP. I haven’t posted a song there in a while!

https://www.chevyhhr.net/forums/www....ad.php?t=55045

 

"After market pioneer speakers."

 

Seems he installed them to replace the OEM speakers.

 

"the elderly couple did not install anything"

(I am suddenly taking offense at "elderly", I guess because I am almost 70 and the wife is 80)