I have an indoor/outdoor thermometer to keep track of how hot the back of my Expedition gets. I drive pretty regularly with two dogs in the back, and over the summer and winter the temps can get a little extreme.
I need to be able to take it out to keep an eye on it remotely (it has about 1/4 mile range) but also have it not rolling around while I drive.
There was a coin holder there that I popped out, and used as a template for an insert to keep this mounted semi-permanently.
Printed with kinda crappy Amazon Basics PETG. If it holds up well, I'll reprint it with better quality black PETG so it matches the car better.
I'm curious how it holds up as well. I was printing a little deflector for my air vent out of regular PLA, and on an 85 degree day the PLA warped in just a couple of hours. I finally have a design I'm happy with, I just need to print in a better material and all I've ever printed in is PLA.
I've made Car seat button pressers and chapstick holders for my car that gets plenty hot and have never had any problems with PLA. They are thicker prints so you might have problems with thinner prints or if you live in a hot climate. I live in a fairly hot in the summer and cold in the winter climate.