From Jim Northway at Fluke’s “Test Tool Tips”
Creative continuity checks:
Dept. of Transportation is responsible for plowing and maintaining clear, safe roads in the winter months. All of our trucks and most of the other equipment
has high voltage strobe lights for visibility in the blowing snow and night operations. We use several different products for melting snow and ice, depending on conditions, all of which are very corrosive to any exposed wiring
and conductive. An arcing short to ground will cause strobes to quit working but when wiring
is dry, in shop tests are inconclusive. Due to the high voltage it's not safe to check live circuit. I use my Fluke 87V and use a table salt
brine in a spray bottle to find the intermittents. I connect the meter, in the diode check mode between the strobe connection and ground. I then spray the harness with the brine and when the bad spot is sprayed it completes the circuit and the meter beeps and shows continuity. I am able to get them fixed and back out on the road quickly.
A MegOhmMeter can also be used to trace wiring damage, when the circuit is not live.