GMC Repair: instrument panel lights turn off then go back on, interior lighting, overhead light

Question
QUESTION: Hi
I have a 2003 Sierra 2500HD 4X4 6L (115,000 km)
I just bought it and on the way home(of coarse)it was dark out  and the instrument lights,overhead light and temperature control lights went out. I thought that it was just a fuse but when I turn the key off it resets and works for a few minutes. It is not related to bumps or shorts as I just sat still and after turning key off then on the lights went out.Is there sensors for light dark that could be faulty or some control box. I have no idea where to start on this problem.Thanks in advance!

ANSWER: could be a faulty BCM that contorls most of the interior lighting

---------- FOLLOW-UP ----------

QUESTION: thanks.Where is it located in this truck. I'm assuming this is a high priced part and once I change it I'm stuck with it whether it fixes the problem or not.If I take it in to a dealer can they test if bcm is good or will they have to guess as well. Last question can you point me anywhere to get an idea how to replace the bcm.Thanks for your time thus far

Answer
according to GM global diagnostics, if the TBC 2A fuse is not blown, then you are to verify there are no broken wires in the backlighting system, if not then the next step is to replace the BCM,  Replacing it is pretty straight forward, remove the knee bolster panel from drivers side, to the right you will see the module, unplug all connectors and unclip from bracket to remove, only difficult thing is that it will need to be programmed to your vehicle, best of luck