Need advice - To drill or not to drill

OK, so I learned the hard way never but never drill into the sides of a freezer, but what about a refrigerator? Now that I have my keezer, I'm turning the old fridge into a fermentation chamber. Would you drill a small hole into the side? Is the door the only "safe" place? I need a place to run the bulb for the temp controller. and power for the heat source (when needed). Help?

What I would do is drill a small hole <1/4 inch just barely through the metal outer skin. Then I would take a thin metal rod and poke it through the foam feeling around for a refrigerant line. If i found one I would start over a little higher or lower. If no line found then I would drill the rest of the way through with the 1/4 inch bit. Switch to the proper size hole saw and again carefully cut a hole in just the outer skin. Remove foam with an x-acto knife. Drill inside to desired diameter. Enjoy a homebrew.

So I guess its not like the freezer where I got the "hiss" as soon as I penetrated the outer skin (metal)? It was like a chamber of compressed air not a coolant line.

Well, I decided what the heck, why not. So I pulled the back off the fridge to expose the compressor and what-not, looked for the bottom corner curve & figured that would be a pretty safe place to drill as no coils should be in a bend like that, so either I was right or lucky, no issues with the drill! Ran the power for the light and the bulb for the temp controller.

So this is one of those analog controllers that changes states on temp fall and opens at set point. (kills power once the temp is reached). Now what do I do if I want to use the heater? I'll need it to stay closed until temp is reached (rise) and 'then' open. Can you wire the switch backwards or do you have to buy a switch that opens on temp rise?

I guess worst case is just to use this controller until this fall when it turns cold again and just build a true 2 stage controller. ugh!