Hello:

I have an '06 MC w/3.5 flex fuel engine. Recently, I've experience some battery drain issues so I purchased a replacement. Well, I just realized the radio/lighting etc. does not shut off once the key is removed from the ignition.

Would this be a faulty door switch causing the problem? I don't see the little push pins like you did on older cars so I'm lost.

Anyone else experience this?

 

The door jamb switch like there are on older cars in made into the door latch assembly inside the door. I had the same thing on an 06 LT I just bought. The radio and cluster, etc would stay on after door opened and key removed. My 06 SS and 11 impala everything cuts off as soon as door is opened no matter if key in ignition or out. However on my 06 LT, as well as other vehicles after 10 minutes the battery rundown kills power so I never had a problem with battery.
Luckily for the 06 and 07 montes the same door latch is in impalas so I plan to go grab one next time at the bone yard from a donor car.
if your car isn't shutting down after the 10 minutes, check the relay, it may be bad or removed. last car I saw that didn't shut down, someone had removed that relay for battery rundown protection.