I needed to check a good number of harnesses and came up with the idea of making an Arduino UNO based Harness/Cable Checker.

The Enclosure was made using Fusion360, (you can find some good tutorials on YouTube, like this one: https://youtu.be/E0bhdr84FNU?si=XYgs8BNgmosF2alE)
The lid snaps-on, with the harness connectors (in this case a Molex on one end, and an AMP connector at the other end) on the sides (but feel free to modify as needed), a 16x2 LCD screen, and a simple Push Button on the top lid.
The internal posts were for holding a set of MUX boards so we could cover all the connections using a single ADC port on the Arduino.

The enclosure could be used for simple projects housing an Arduino UNO. I recommend rotating the box with the opening up, as well as the lid with the attach feature up, for easier printing.