Again if you leave the hatch open and the lights don't go out in about 20 minutes something is wrong. One issue is if you keep opening and closing doors you will keep resetting the timer. The 20 minute feature is to keep you from draining the battery.

Having said that, if you are playing the radio it will drain the battery faster than just the lights for sure. The HHR battery is fairly small. I leave my hatch open for hours while I am working on projects and never have a battery drain issue.

just my $0.02

 

You have a 2006 not a 2009 .

 

What he said. Yes, mine is a 2009.

What you are referring to is on page 3-18 of the 2009 HHR Manual:

Battery Run-Down Protection
The vehicle has a battery saver feature designed to
protect the vehicle’s battery.
When any interior lamp is left on and the ignition is
turned off, the battery rundown protection system
automatically turns the lamp off after 20 minutes.
This prevents draining of the battery.

This is for when all of the doors are CLOSED not with any of the OPEN. When the doors are closed and you have the reading lamps on, it will automatically shut them off to prevent battery drain. However if any door is, the lights will stay on continously without a limit.

Dome Lamp
Move the lever to the following positions:
9(Off): Turns the lamp off, even when a door is
opened.
1(Door): Turns the lamp on whenever a door is
opened.
The dome lamp and mirror reading lamps will turn on if
the lever is in the door position and the instrument
panel brightness control is turned to the brightest setting.
See Instrument Panel Brightness on page 3-17.
+(On): Turns on the dome lamp.

This is the part of the manual of page 3-17 that still has the information from the 2008 manual regarding the dome light. As you can see (and Y'all can pull it up) you would think by the manual that you have a dome light with the override switch. This was not correct as GM meant to edit it out of the 2009 manual but its in there.

Blue