Technical tidbits

From LED lighting technology, to male pin lighting/harness applications, to multiplexing issues – today’s technology means that the end user should be able to design lower costs and longer life and product quality into all lighting and harness uses. However, most fleets state that electrical and lighting problems are the source of their most constant problems, and costly. Regardless of an end user’s size, vehicle safety lighting, wiring, and electrical system can be major sources of frequent failure and high maintenance costs. Part of Grote's mission and customer goal is to provide problem solutions and not simply product. Together the industry, led by Grote, has collaborated over the last decade to reposition the future in industry lighting and help control costs and downtime for end users. There is a general identification of eight basic causes of those system failures of safety lighting products, and below you will find them defined. Given Grote's mission of solving problems in the market, it is key to have an understanding of these causes in general terms and the keys to solving the problems and offering a total vehicle system solution. It is about saving time, money and providing industry solutions that will lead systems design into the next century.

  • Major Causes Of Lighting Failure
  • Cleaning Materials for Lenses
  • Tips to prolong equipment lighting
  • Damaging Issues of Safety System
  • Trailer Wiring Data
  • P2 and PC Lamp Installation

    • The causes of lighting failure are well known, although they differ as to the most prevalent depending on the specific environment a vehicle is working in. For example, a heavy duty multi-trailer rig traveling at high speeds in winter will need to prevent a different set of failure modes than a farm tractor or a piece of construction equipment. In any case, Grote knows the best ways to keep electrical safety systems operating at peak performance regardless of the specific situation.

      Major causes & How to prevent them

      1. Corrosion in the wiring

      The highway environment is one of the most toxic environments encountered by vehicular and specialized equipment. Water is bad, but salt water and ice buildup is worse. The basic problem is that salt water corrodes wiring at a more rapid rate than plain water and also wicks farther along wiring than rain water. Here’s what to do before the ice and salt brine season starts.

      The trick is to completely seal off all wiring from the elements. Here’s how:

      • Check all your connections. Loose connections are prime water entry points. Make sure all exterior sections of connection surfaces are liberally coated with anti-corrosion grease and check that the connection closes correctly and forms a tight closure.
      • If wiring goes through a hole in a trailer wall or partition, make sure the hole edges are covered by a grommet or similar material. If not, the wire will fray and short out. Frayed wiring is a perfect entry point for salt water. It will enter any opening in the insulation and wick salt water through the harness, so inspect all wiring and make sure all frayed wiring is spliced out and properly sealed. There should be no taped splices in your wiring. All splices should be heat sealed with shrink splices. This is always true, but winter grime build up often hides splices that need attention.
      • Any wires that hang down from their correct runs on the exterior of trailers are prime candidates for ice buildup. As ice accumulates, the increased weight pulls on the wiring, causing more fraying, loose, or severed connections, lamp dislocations, and stress on splices. If a wire or cable pulls out completely, you can lose your lighting. Once again the remedy is obvious. Wiring needs to be tucked and tied up using plastic tie wraps into its run so that ice can’t dislodge it. If a wire has to be exposed, a tie wrap can often prevent failure due to ice buildup. Check to see that drip loops are not in a place where unseen ice builds up. In winter, drip loops no longer always deflect water as they do when the temperature is above freezing.
      • Wires that are incorrectly spliced and/or are beginning to corrode are not good conductors of electricity. As a result, lamps, especially ABS indicator lamps or stop/tail/lamps, will flicker or stop working altogether, creating a dangerous and often illegal situation.
      • Battery and nose box connections need to be checked to make sure the required current is present. Terminals should be cleaned, tightened, and greased to protect the battery and the overall electrical service.
      • Choosing a harness design that uses male pin lamp terminations is always a safer and better idea in all seasons, but especially so in winter. If ice does succeed in pulling wiring free of a lamp, the free wire will not short out its circuit by contacting metal surfaces on the trailer.
      2. Sealing Out Corrosion

      Dielectric grease has been around a long time. It works great when it is used correctly, but it’s trouble in a tube when misapplied.

      Originally used on AC motors to protect them from shorts from exterior intrusion, dielectric grease’s ability to protect electrical connectivity over long periods of time soon found another role as a barrier to corrosion when used on electrical circuitry. Its protective properties allow trucks and trailers to operate over long periods of time in the face of ever more corrosive salt-based solutions used in larger amounts every year on Northern highways.

      When grease was first used in harnesses, it wasn’t necessarily a marriage made in heaven. Some of the early compounds dried out prematurely. On top of that, many earlier rubber and synthetic rubber harnesses could not stand up to the chemical compounds in the grease, which would leach into the rubber compounds of the harness, debilitating its resistance to salt water corrosion though subsidence or cracking. Our industry-leading Grote UBS™ Ultra Blue Seal harness system solves all those problems.

      Grote UBS™ harnesses use a soft, low durometer PVC that provides the best results when it comes to harness resistance to the effects of dielectric grease. UBS harnesses are resistant to chemical and UV attack, stay flexible, and won’t harden or crack. When used correctly with our dielectric grease, harness connections can remain free of corrosion over the lifetime of a trailer. The key word here is “correctly”.

      3. Harness to Harness Connections

      Whenever a harness connection is opened, either harness to harness or harness to lamp, a specific procedure should take place. Old grease should be cleaned out with a Q-Tip or similar tool, taking care not to gouge or scratch any part of the harness. Make sure the grease applied covers the pins themselves. New grease should be applied, not so much because the old stuff goes bad, but because adding new grease on top of old may be too much for the size of the connection. This creates a hydraulic effect, preventing the harness sections to close properly, preventing a complete seal.

      Grote recommends that grease be put in both sides of the harness connection and recommends that for best performance, when available, a grease collar can be installed over the harness to harness connection as shown in the accompanying illustration. In this example, the collar contains the grease and helps prevent the connection from coming apart over the life of the trailer.

      4. Harness to Lamp Connections

      There are female lamp pin/male harness designs and male lamp pin/female harness designs. Both designs have their adherents. Grote provides both AMP and male lamp pin designs. The connector style we use is determined by our customers.

      We prefer the male lamp pin design because after years of testing, we know that a greased male lamp pin design outperforms other designs. This style allows a super-tight harness within the lamp seal that does not relax with age, even in the presence of grease. Also, this design stands up better to ice loading on an exposed harness, the weight of which can pull the connection apart. And if the connection does let go due to damage from events such as a tire tread delamination, there is much less chance of a short circuit from a loose female harness connection connecting with an exposed metal part of the trailer. Regardless, of which connection style you choose, it is important not to use too much grease which can prevent a connection from closing correctly.

      5. Which Harness to Spec – Custom or Modular?

      The idea is to never compromise the harness by adding ways for salt intrusion to come in contact with its wiring. On the one hand, modular harness connections must be kept inviolate by using techniques described above. On the other, a modular harness gives you the ability to change or add to the harness without adding a splice which can add a salt gateway to the wiring if not done correctly. For example, if the harness is damaged, by going back to the last connection a new pigtail or harness section can be added without compromising the harness system.

      A custom harness minimizes the need to splice a harness, but only when it is used as originally designed. Thus, when an improvement becomes available for the lighting of the trailer or the harness is damaged, splicing may be the only solution.

      Grote provides both styles of UBS™ harnesses and can consult with you to find the best solutions for your particular needs.

    • The use of solvents and/or cleaners which are not compatible with polycarbonate will result in the softening, crazing, and/or cracking of the plastic part. This is especially true of polycarbonate lamps and mounting bases which may be under stress in their normal applications.

    • The use of solvents which are not compatible with polycarbonate will result in the softening, crazing, and/or cracking of the plastic part. This is especially true of polycarbonate lamps and mounting bases which may be under stress in their normal applications.

      General tips to prolong equipment lighting

      Never use a test probe to pierce wire insulation
      • When troubleshooting lighting complaints never pierce the wire insulation
      • Wicking action takes place which causes moisture to travel along the wire strands and corrode critical connections along the complete connection – “salt creep”.
      • If probing a harness or wire is unavoidable, make sure the puncture is properly sealed – understand that the Ultra-Blue-Seal™ system is a modular sealed system that must not be cut into – especially for warranty purposes. Testing should take place at each termination point along the main, rear sill, jumpers, pigtails and lamp itself. Replacement then does not need to be the whole system, but simply the damaged extension area.
      To correct voltage problems, discover the real cause
      • Under-voltage often is caused by poor electrical connections. To correct under-voltage or illumination problems, don’t just turn up the voltage, find out what caused the under-voltage problem.
      • Over-voltage is causes major damage to lamps and batteries.
      Many discarded lamps are still in good condition

      Do not simply “assume” when solving lamp problems – explore all avenues to make sure you are identifying the true source of a problem. Make sure you are not simply fixing a symptom of a greater problem.

      First, test with either a meter, power supply, or battery. Our male and female testers are perfect for this (87810 and 87820).

      Then if you desire, open the lens on a discarded lamp and examine the bulb. It will help tell you what failed. For example:

      • A bulb with stretched or broken filaments was subjected to heavy vibration.
      • A yellowish, whitish of bluish glaze on the bulb indicates a rupture in the bulb glass envelope and a possible leak.
      • A dark, metallic finish indicates old age.
      • A black, sooty bulb indicates a poor seal in the bulb.

      Test all lamps one time before you discard them. General findings show that up to 40% of all lamps sent back are still in good operating condition. The ones that aren’t working can be turned over to your lamp supplier.

      All lamps will last longer if they run cool

      Dirt on lenses increases the heat, so keep them as clean as possible. Other people can see your rig, and that is one of the purposes of the lighting system (besides safety) – to be seen.

      Heat is one of the most damaging conditions to a standard incandescent bulb, right up to a cluster of LEDs, which can also be damaged by heat. For this reason the Grote 4? LED offers significant heat benefits against the competitors plastic housing as the anodized aluminum dissipates the heat into the trailer body.

      All lighting must breathe to eliminate the damage from heat build-up and thus shortening of bulb/lamp life.

      Treat the electrical system as you would the chassis

      Lubricate sockets, pigtails, battery terminals and connections with Ultra-Seal Sealant (99170) “non-conductive” anti-corrosion compound. Use the proffered Grote small tube of grease for lubricant.

      The purpose of the sealant is to totally encapsulate and protect against corrosion and water.

      Do not use sodium-based greases. Sodium will emulsify if it ever comes in contact with water.

      Inspect for improper ground connections
      • This is a major cause of lamp failure, especially when the trailer is used for a ground.
      • When lamps are grounded through the lamp housing, make sure there is a clean connection (ie. metal to metal).
      • Also, a fifth wheel ground strap may be used for added protection on the chassis ground system.
      Look for loose, bare or unsupported wire and fixtures

      Harnesses and wiring should be on the underside of top frame members rather than on the bottom where dirt and road splash collect.

      Always replace wiring trailer light cables and harnesses with an equal or heavier gauge of wire (From original specifications)

      If you don’t, you may cause unnecessary problems. See our catalogue for additional wire gauge information on specification. This product and process mentality provides for proper gauging.

      On older trucks, you should never crank the truck while any lights or accessories are on

      Also, never leave markers/clearance and hazard lights on when parked against a dock. Melted lenses are a sure sign that the vehicle has been parked against the dock while the lights were on.

      Always remember that the trend is towards reduction of power consumption, and voltage surges are extremely damaging to wiring or lighting.

      Inspect the grommets that house the lamps
      • As the grommets age, they eventually will deteriorate from sunlight, ozone and harmful chemicals.
      • New grommets restore shock protection, security and improves appearance.

    • The following are the 3 most damaging vehicle element items: a) environment, b) abuse, and c) time.

      Before even examining them in the context of on-road vehicles, consider a parallel by thinking about the electrical wiring system in any private residence – house. Problems are seemingly always kept to a minimum in a well-maintained home.

      • Environment – mostly at its best, all wiring is in conduit protection in the building walls.
      • Abuse – the greatest common abuse is an overloaded circuit. It results in blown fuses or open circuit breakers.
      • Time – almost indefinite.Now using that above example of the building’s wires, put it in the context of a trailer’s wiring system.

    • Wire is used to carry current from the battery through the vehicle to various electrical components: lights, instruments, etc.

      In automotive use, the grounded return system is used almost exclusively. In this system, a single wire is run from the battery through switches to the load and the vehicle itself provides the ground or return to the battery.

      How to Select the Correct Size of Electrical Cable

      It is important to note that all electric-components have a good ground. In a combination of vehicles (tractor-trailer) it is important that a good and adequate size ground wire be provided between the two vehicles to carry the current.

      Wire has certain resistance to current flow, the smaller the wire, the greater the resistance.

      Also as the amount of current (amps) increases, the resistance (ohms) increases.

      For a 12v system there are two factors to be considered:

      • Voltage drop is the primary consideration in selecting the proper electrical wire size. The length of wire in a circuit is the major contributing factor to voltage drop.
      • The Current carrying capacity of the wire. The heavy load in an undersized wire may increase the temperature of the PVC insulation above a safe level of 180º F.

    • The federal government requires clearance, side marker and identification lamps on all vehicles greater than 80 inches in width. All of these lamps must meet the same photometric requirements, which call for light that is spread 45 degrees to either side of the lamp center-line.

      P2 and PC Lamp Installation

      Clearance, Side Marker, and Identification Lamps

      The federal government requires clearance, side marker and identification lamps on all vehicles greater than 80 inches in width. All of these lamps must meet the same photometric requirements, which call for light that is spread 45 degrees to either side of the lamp centerline. (See diagram.) The SAE identification code for these lamps is P2. The purpose of clearance lamps is to indicate the width and height of the vehicle, so these lamps must be mounted on the front and rear of the vehicle, as close to the top and sides of the vehicle as is practical. The purpose of side marker lamps is to identify the length of the vehicle, and they must be mounted as close to the front and rear of the vehicle as is practical. The purpose of identification lamps is to indicate to other drivers that the vehicle they are mounted on is a large vehicle. Three of these lights are required on the front, and three on the rear of the vehicle, centered and as close as possible to the top, and spaced between 6" and 12" apart.

      Combination Clearance and Side Marker Lamps

      One cost-cutting measure that is legally allowed is to combine the functions of the clearance and side marker lamps into a single lamp. This is done by mounting a lamp with a very wide light emission pattern on the upper corner of the vehicle. In order for these lamps to function properly, they must be mounted at a 45 degree angle. Combination clearance and marker lamps spread light 90 degrees to each side of the lamp centerline. When mounted on the corner of the vehicle at a 45 degree angle, this allows them to point light to the same angles as separate clearance and marker lamps would. (See diagram.) The SAE identification code for combination clearance and marker lamps is PC.