Electrical problem

[jprov1768]

I have a 2001 silverado, 6.0L, 2500. (67,000 miles). I just noticed that when I shut the engine off, close the door, after about 30 seconds when the interior dome light goes off, the gas and temp gauge activate and stay activated until I open the door or click the lock/unlock device. The battery is relatively new and seems properly charged. I get no charging system warning lights on the dash message center. I have called a couple places (auto electric and dealer) and all have never heard of this phenomenon.. Has anyone had a similar problem and had it diagnosed, or anyone have a clue what could be going on?????? I appreciate any incites. Thank you..