Dealing with electrical problems
Mar 1, 2005 12:00 PM, By Rick Weber
IN 2003, Grote Industries decided that there was a market for a training program on the fundamentals of electronics for mechanics who change out trailer lights or troubleshoot wiring.
So Grote produced a Know-How Self-Study Guide, The Basics of Electricity and Vehicle Lighting, which starts with Ohm's Law and then deals with electrical flow, the impact of wire gauge on electrical systems, and various types of connections.
That book was so successful that Grote last year released another guide, Vehicle Lighting Installation and Troubleshooting, which deals with the hard-core issues technicians face.
Grote's efforts were recognized last November when the company — a leading designer and manufacturer of vehicle safety systems — was presented with a Women's Automotive Communications Award at the seventh annual Car Care Council Women's Board reception during the Automotive Aftermarket Products Expo (AAPEX) Show in Las Vegas. Grote, which is headquartered in Madison, Indiana, and has manufacturing plants in Monterrey, Mexico, Toronto, and Waterloo, Canada, won the Best New Training Materials category.
“We were really fired up,” says Dominic Grote, vice-president of sales and marketing. “We knew this had an impact with our customers. We had been getting some positive feedback, but the award really solidifies that the market — our customers, the end users — is really hungry for this kind of information and these kinds of tools.”
The guides, available from Grote for $25 each, contain a list of questions at the end of each chapter. The technician can study at his own pace, then take a 72-question final exam when he completes the book. Grote grades the test and sends it back along with a certificate.
“A lot of fleet customers have dollars set aside every year for training,” Grote says. “Sometimes they have sophisticated programs and they identify things as they go throughout the year: ‘Maybe this person needs special attention.’ This is set up as a tool for a maintenance manager to say, ‘Yeah, this is something we'll invest in. I want to see your test scores.’”
Grote says the guides are another value-added service to its distributors, who are interested in selling product and providing product solutions for problems that fleets might have.
“This gives people a comfort level with one of the highest cost-maintenance issues for a fleet — and that's electrical,” he says. “I can't tell you how many times we have warranty parts come back, and the parts are good. The problem wasn't necessarily in the lamp; it was in the wiring or a short or some other area. The first thing they do is take the lamp off and put on a new one, and it still doesn't work. They go back and work their way backwards instead of the other way around.”
Vehicle Lighting Installation and Troubleshooting starts with the EAT Principle, concluding that environment, abuse, and time are three of the most often cited factors in vehicle light and wiring damage.
Tim Brooks, Grote's director of product development, says the wiring's environment is critical to its proper performance and durability. The wiring is designed to carry a specific electrical load, and increasing that beyond the designed tolerance of the wire can produce increased heat and possibly even a fire.
Vehicle wiring, more so than wiring in a building, is affected by time because vehicles operate in harsher environments, with trailers running year-round in everything from scorching desert heat to sub-zero cold. Components are covered with magnesium chloride, calcium chloride, and road salt. “Salt creep” starts when salt water enters a wiring system through a cut, abrasion, or faulty connection, then settles in critical junctions, ultimately producing an intermittent defect or total failure. In addition, the components are subjected to the pounding and loosening effects of severe vibration, with wiring connections being particularly prone to damage.
Abuse comes into the picture when power is supplied to too many lights on a circuit, which can cause substandard light output, overheating of the wiring, or total failure. Sometimes numerous splices of smaller lengths are used instead of one piece of properly sized wire — or shrink tubing might not be used to protect a splice from the elements, or system elements might be assembled without using dielectric coating.
“Over time, the effects of environment and abuse just seem to get worse,” Brooks says.
He says that abrasion occurs when wires are allowed to touch wear points such as frame members and other vehicle parts. Once the insulation is worn away, a grounded circuit can be created when bare conductors contact a ground source. The result? Corrosion and the raising of resistance in the circuit, or excessive wear leading to fracture and an open circuit.
He recommends using proper routing and coverings, properly securing wires to restrict undesired movement, and replacing worn coverings such as loom, convoluted tubing, or spiral wrap. If there is the possibility of contact with moving parts such as lift gates or wheels, care should be taken to ensure the covering is secured correctly. In addition, grommets should be used where wires pass through and around metal parts.
“We've even done some custom grommets for some of our bigger trailer customers, where the rubber grommet goes through holes so you don't have that abrasion between the wire and sharp edge,” Brooks says. “It's really just keeping an eye on detail and thinking about vibration and how the wires are moving as they go through the life of the trailer.
“There are also things you can do if you're a small trailer manufacturer: heat-shrink tubing or convoluted tubing you can put through a hole that gives you an added layer of protection.”
Heat-shrink tubing contracts by a ratio of 4-to-1 under application of heat. It's available in PVC, polyolefin, silicone, and fluoropolymers, and comes in single or dual wall.
Brooks says it's important to view the harness and lighting as a system.
“You can't just pick anybody's harness and put it with anybody's light,” he says. “We work very carefully at developing a good interface between the light and harness. The critical thing in the entire harness and light is to seal it and install it so you don't get any of the nicks, or, if you put it through a hole, make sure vibration and abrasion are not going to cause the wire to crack.
“If you back into a dock and crack a lamp, or if you have a lamp go out, don't troubleshoot by poking into the harness, because once you break that seal, moisture can start to travel throughout the harness.”
Brooks says that when noticing a lamp has failed, it's wise not to assume that the cause lies only with the lamp. Examine the lamp itself for clues to failure: A lamp with stretched or broken filaments typically has been subjected to heavy vibration; a leak in the glass envelope is likely if there is a yellow, blue, or white haze on the inside of the lamp; old-age failure shows as a dark metallic finish; and black sooty deposits on the inside indicate a voltage surge that has “burned out” the filament.
Brooks says lamp and lighting systems failures can be caused by the constant pounding that truck components are subjected to. The filament weakens and then breaks. The solution? Install lamps with shock-mount mechanisms that cradle the lamp and cushion it — such as Grote's Torsion Mount II or Grote's newest anti-shock technology, Gel-Mount, which uses a soft gel material to hold the lamp in place while dampening the vibrations and protecting contact points from moisture and corrosion.
In addition, typical incandescent lights can be replaced with LEDs, avoiding the problem of road shock.
“They talk about LEDs lasting 100,000 hours, but that really depends on how you build LED lamps,” Brooks says. “We pot most of our LED lamps — that takes away the vibration. That way the board and components don't move around. We also specially formulate our potting; we have a company that does a formula just for us.
“Just because someone goes out and buys LED lights, they may or may not be good lights. They may not get a light much better than an incandescent.”
© 2013 Penton Media Inc.
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