Well, I finally got bit with my first issue with the HHR.(08 LS) I was driving home from work yesterday and had the windows down enjoying the nice weather, stereo playing with my MP3 plugged in. It's the mid-grade XM radio/ no subwoofer, just the 6 speaker system. I noticed as I slowed down for a traffic light the stereo sounded different and thought it was the cable for the MP3. I pulled the plug and tried a local station and it sounded the same. Pulled in the driveway and noticed the two passenger side speakers were out; nothing! The tweeter was working but that's it.
So where do I start? Waterfall...Doorpanels??? UGH!

 

Acknowledging the possibility of two blown speakers at once(unlikely) or a wiring issue most probably there's a problem in the radio head.That means it'll have to be pulled and sent out to your local Delco radio service facility where it will mosy likely be exchanged for another head unit.

 

X 2, I'll have to agree with Tony here, more likely than not your head unit is packing it in.

 

Thanks guys. Hate to take it in under warranty just for that. I went out a bit ago to run an arrand and the front passenger speaker was working again but the rear was not. Maybe I'll pull it apart myself and check the plug for the speakers...

 

That's what warranty is for.......