Making Short Work of Corrosion
October 2009, TruckingInfo.com - Feature
One of the main concerns in front of the Technology and Maintenance Council of the American Trucking Association is corrosion caused by road chemicals. The problem has escalated in recent years with the adoption of magnesium and calcium chlorides
as a highway de-icer in preference to sodium chloride (ordinary salt). The newer chemicals' physical properties make them cling to the roadway and de-ice better, longer and almost certainly cheaper.
But these chlorides are a lot nastier than road salt as a corrosive because of these same properties. It hangs around, does not wash off easily and is hygroscopic. Hygroscopic means it attracts moisture from the air, so it never really dries out. In fact, it is sprayed on dusty desert roads where it attracts the even minimal moisture in the air and keeps some of the dust down as traffic passes.
Unfortunately, this perpetual wet state means that the corrosive chloride solution will wick up within vehicle wiring systems if it can find a point of entry. Companies such as Phillips Industries, Truck-Lite, Grote, Peterson and others go to extraordinary lengths to encapsulate electrical components and wires to keep the water and salt solution from getting between the electrical conductor and the plastic sheathing of the wiring.
Then along comes the tool truck to the shop door and technicians pour out to see what is the latest cool tool that can speed their way as technical professionals. And if they don't have at least one already, they'll purchase that sharp-pointed probe they can poke through the wiring insulation to check for electrical continuity in a circuit. This, of course, immediately undoes all that careful work by the engineers, manufacturing people and truck makers who try to keep all the wiring insulation intact.
There has to be a better way. And Dan Sullivan, a fully qualified technician trainer and trade school lecturer, says he has it.
Quite a few fleets have tried his answer and agree with him. Not only is the circuit testing non-invasive, it brings some excellent additional functionality to the party.
The "tool" is Teslite, a set of special leads that works in concert with a digital voltmeter - any digital voltmeter, though Dan says he likes the UEI DM 393 for its ease of use, accuracy and cost.
Substituting the leads and adding one extra button to press when testing allows the voltmeter to load a circuit and identify wiring faults fast. It doesn't damage wiring, as it has SteadyPin tips that Sullivan says touch on the male connector pin in a circuit.
The technician reads voltage just as the test procedure tells him in a fault-finding tree, using the test leads and the voltmeter in the usual way. When the button is pressed, a voltage drop on the meter shows there is corrosion in the circuit.
But that's not all you get from Sullivan. You also get exceptional training in how to understand some of the nuances of a voltmeter like the UEI DM 393. You can see these for free at www.brighterideas.com on the video tab. Go to "training" and watch Dan show you how to use the "ghost voltage" reading to detect an open circuit. He holds the leads together to give a straight zero, which in a test situation means a short to ground. Watch him use the push button for a load/corrosion test - and the test procedure will show whether it's in the positive or ground side - and you can quickly see how Sullivan's tool can take two days of frustration chasing wiring faults down to maybe 10 or 15 minutes.
Sullivan says he's sold several thousands of the tools through his training, by word of mouth and through his web site. If you want to know how well one major fleet has accepted the tool, look at the part numbers for the Teslight: these's a Caterpillar, a Volvo and a UPS part number for it!
If you share your technicians' frustrations with chasing wiring problems, are suffering days of downtime or recurring problems, fitting new components only to be faced with the same problem, go take a look at Sullivan's demo in his training video. It will likely make you a believer in short order. Pun intended.From the September 2009 issue of Heavy Duty Trucking.