This is what I’m working with. 
Discussion
Oh. You could cram an old school lightbulb in the space below and that would probably work if you can't get a heat tape, though, I think you could fit a heat tape even in those tight quarters.
That’s actually a good idea. There is a 110 power plug the bottom of the box. I’ll have to look into that once I get it thawed out. Thanks for the idea.
You're welcome! I'm dealing with my own freezing issues, and I've learned a bunch. Happy to pass ideas along that keep the water flowing!