I recently bought a Flir One device and found it very useful to find bad cables and connectors on my 3D printer.
In this case the connector was so hot it started to melt!
This Dupont cable was used to power a NEMA 17 motor. I really need to buy better cables and connectors!
I blame @Jeremie_Francois for inciting me to buy one 
How it work ?
Hotend or Heated bed hooked up with DuPont connectors? Or was it to a stepper motor?
Helpful info for people who may have similar setups.
I bought a Seek Reveal for hotend and extruder design, it works nicely. An additional use was when a server in one of our datacenters went down the thermal camera allowed me to identify the overloaded PSU in the rack within seconds.
@Teo_Jerah A Flir device can show Infrared lights. With this info, an app can then measure the temperature remotely without contact and produce this image.
Dark/purple = cold ; Bright/Yellow = hot.
Check out the temperature scale on the right of the image.
I will post later pictures of my heatbed, this helps a lot seeing exactly how accurately it heats up (center vs corners).
Wow cool…
@PrintinAddiction Oh no I don’t use Dupont cables/connectors for the heat bed! This would burn in a second! lol
I use these connectors/cables to power the NEMA 17 motors. While Dupont cables are cheap and easy to connect, connectors are not reliable and cables section are too small. I will switch them with bigger cables as soon I as can now that I really see how they heat up.
BTW the board (3rd picture) is a MKS Gen powered in 24V.
Honey… I know I promised I wouldn’t spend too much with my 3D printer… but I need a FLIR. 