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Major Causes Of Safety Lighting Failure

Reason #1. CORROSION

Causes of Corrosion:

Water, dirt, salt and any other road contaminants can enter a lamp or connector, providing an electrical path which can vastly accelerate corrosion.

Control of Corrosion:

Corrosion cannot occur when the bulb is sealed within lamp housing. For example, Truck-Lite's sealed lighting products.

Further Protection:

Connectors should be sealed with non-conductive grease. Areas like electrical contacts, circuit switches and junction boxes.

Purpose of sealant:

To totally encapsulate the area to protect it from the elements.


Major cause of shock & vibration:

Constant road pounding experiences when a tractor/trailer is traveling down a highway can cause filaments in a bulb to distort and prematurely break.

In addition, shock and impact damage are sometimes caused by something other than road vibration.

    Some examples are:
  • Loading container chassis on to a truck chassis
  • Dump truck loading or tailgate banging
  • Loose mounting of cargo hardware
  • Unloaded operations
  • Impact with stationary objects such as poles orloading docks

Solution to shock & vibration:

Install a lamp designed with shock-mounted mechanisms that cradle the bulb and absorb the effects of shock and vibration that otherwise would be transferred directly to fragile bulb filaments or LED lamps.

Baseless bulbs:

Suspended to endure heavy-duty applications more than traditional S-8 non-shock-mounted bulb units or standard J-slot bulb sockets.

Advanced Technology - LED's

  • LED's rated at 100,000 hours of operation
  • Solid state, and much less susceptible to shock and vibration
  • Electronics are completely sealed in epoxy


Suitable wiring:

Wire size or gauge is very important, as the use of a wire gauged too small can lead to dim or intermittent operation, excessive voltage drop and present a potential fire hazard.

Avoiding excessive voltage fluctuation:

Suitable Wiring has a positive effect on product life and safety. A sealed waterproof wiring harness system based on electrical load of the vehicle should be selected.

Stranded copper wire should be used. Copper wire has a higher current carrying capability than an aluminum wire of the same size, is moreflexible and less likely to break.

Harness systems available that:

  • Exceed industry standards
  • Eliminate troublesome splices
  • Seal out the elements
  • Provide a common ground
  • Last the life of the trailer


Always a difficult problem for bulb life, as many as 60 percent of bulb failures are not as they appear. Many failures caused by voltage spikes as a result of load dumps (such as starting the engine with the lights on). Other sources ofover-voltage conditions are heavy draw electrical devices such as lift gates or welders. When the units are turned off, they can create a back lashin the form of a voltage spike.

Voltage regulators that are set too high can shorten life as well, in addition to battery disconnection while the truck is in operation.

A good way to specifically protect the lights of voltage damage, is to avoid starting the vehicle or using heavy draw accessories while the vehiclelights are on.

Voltage should be checked regularly to insure the vehicle is operating within a safe range. One volt beyond designed voltage will reduce expected lifeof a bulb filament by more than 50 percent.


Installing a lighting product and harness system that uses an internal ground will help assure an absolute ground-forever because it does not depend only on the chassis ground. Internal ground also helps to eliminate rust and corrosionassociated with chassis grounding.


In the traditional non-shock-mounted bulb units and the standard J-slot bulb socket, corrosion and/or loss of spring tension cause loss of contact. With the inception of the sealed baseless bulb lamp and soldered connections, product life is further enhanced and bulb contact is certain.


Answer to the problem is a super-tough highimpact plastic that's… Impervious to heat generated by the bulb and damage resulting from typical use.

Both lenses and lamp housing should be manufactured of a space-age plastic such as polycarbonate. Using recessed mounts and branch deflector designs further protect lamps from impact damage. Often, lamp lenses are broken or damaged by tree limbs or other obtrusive objects.


Studies have shown that when sealed shockmounted bulbs and lighting devices are used along with sealed wiring harness systems, product lifecan be extended as much as 20 times beyond traditional unsealed bulb units in heavy-duty truck and tractor/trailer applications.

Using an original equipment part that lasts the life of the vehicle, or alternatively requires little attention and minor cost after initial purchase, should be everyone's goal. Technology is available today to design and produce lighting products that can offer 500,000 to 1,000,000 miles of maintenance free service for most applications.

Product life performance can be extended and overall costs of vehicle operation reduced by doing a careful evaluation of the total vehicle lightingsystem… its problems… and the methods to control and eliminate those problems.

This documentation was provided by Truck-Lite Co.,Inc.

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