Probably worrying too much, but...

[guidofatherof5]

Some heat(under tank heater - UTH) will probably aid in some activity and digestion.
What is the ambient temp. of the room the snake is in?

I don't know what size your snake is but I see a huge/dangerous problem with a chicken wire top with duct tape. There is usually an inside lip to most aquariums and a lid(wood, or screen frame)can be easily cut. The center of the wood can be cut out and a window screen material can be put on to cover it. Duct tape is also a no-no.
The top of your enclosure isn't secure right now.

Be sure to introduce yourself in the "Welcome Lounge" so we can give you a proper welcome.
Welcome Lounge

Garter Snake Forum - Garter Caresheet

[EasternBlackNeckedGarter]

Some heat(under tank heater - UTH) will probably aid in some activity and digestion.

If the room is in the eighties, what size/temp heat pad should I get? (Note, his main cave has no substrate underneath, just glass.