Afternoon,
There is a buzzing noise, like the when you put the key in the ignition and you, about to turn the car on. Usually, once you turned the ignition, you noise (buzzing), goes away. It doesn't, not does it, when you take the key out and shut the door. So, yes the buzzing continues and you taken the key, shut the door and walk away. The interior lights go off as normal but that buzzing.... knowing it will under the battery down, i need help, figure out what to fix that buzzing noise. I seen smoke coming from above my fuel gauge on center dash and that's when it all started.

 

I'd start by disconnecting the negative terminal from the battery, then the positive terminal, gain access to the fuse panel and look for signs of trouble.

 

Sounds like the AIR/RIDE is running and getting hot. Causes= Plastic tube loose, broken or burnt into. I had the plastic fall down on my new 1979 station wagon and it melted the plastic on the wires to the air ride pump.. I have had trouble of the adjustments of the sensors slipping and causing the pump to run all the time. GM is a a UNION SHOP run by BOOK LEARNED IDIOTS. The UNIONS have made Nippon and China very rich