Take a look at my sig,
Links to Owner Manuals and Shop Manuals.

 

I have a pair of HHRs, a 2007 and a 2008. The 2007 just started giving me trouble with dim dash lights during the day, the 2008, which I just bought, does the same. I don't have a solution except to bypass the dimmer switch.

 

Not to argue, but if set to AUTO don't the headlights stay on all the time (except in park)? At this setting the dash should be bright, but isn't with many.

 

Set to auto , only the day time running lights would be on. Not the tail lights or the dash board lights.
the dimmer switch on the waterfall controls the instrument panel lights.

 

Dim dash lights during the day, pretty sure that's functioning as designed.

 

Could be the auto dimmer sensor in the middle of the dashboard is covered or dirty

 

Mine always bothered me when going through a tunnel. Off before entering then bright while inside then off again.

 

Night would dim the lights.