Gmc - Terrain :: 2012 - Unknown Noise Under The Hood

I have a newly acquired 2012 GMC Terrain, SLT2, FWD, four cylinder. I have discovered something my dealer has never heard of and knows nothing about, but says it must be normal!!! With the engine (hot or cold) and ignition off, key removed, about 15 seconds after opening any door, rear hatch, or hood, a "clicking" sound starts up under the hood and lasts several seconds. The same thing happens again after you close the door, rear hatch, or hood!! Using my automotive stethoscope, I have traced the sound to the front cover of the automatic transmission where there is an electrical connection. It is very audible at that point.

This is not causing any problems, but I would really like to know what it is and if, in fact, it IS "normal". If it is not normal, I need to get it repaired as soon as possible, as the car is still covered under GM's Certified Pre-Owned vehicle warranty. My dealer rep. could actually hear the "clicking", but was not concerned enough about it to even try to find out what it was!! He just told me it was normal!!