Heat Sensor For Electrical Troubleshooting

One of the things I always like to remind readers about is that the primary by-product of lousy electrical connections is heat. Enough heat, and things catch on fire. That's pretty easy for just about anybody to understand.

What's not so obvious to most people is that there are some relatively easy and inexpensive ways to see if too much heat is being generated. In the photo below I'm checking the quality of the main positive feed cable to the starter motor on a friend's outboard engine.

The infrared heat gun shown is one made by ExTech, but these guns are widely available today from a number of vendors. Radio Shack sells them. I've seen them for sale for as little as $29.95.

So, besides using them to check for engine cooling system problems or to see if your steaks on the grille are at the right temperature, these guns make a great tool for finding loose or not so obviously corroded electrical connections. The way I do this is to scan the cable in question using the red laser light on the gun. This way I can establish a median temperature in the cable in question. With the engine cranking in this example, I close in on the connection with the laser light. If I see a temperature rise of 25 degrees F or more, I am immediately suspicious of the quality of the connection. This is a simple technique that can help you find some elusive problems, and save you from burning your finger tips!

There's a good reason the gun above is also shown in Eds Tool Box.