Big Rig Basics

John Baxter | October 01, 2010

Making Converts

LED lights may cost more initially, but their advantages over incandescents pay for themselves fast


Brad Van Riper, senior vice president and chief technology officer for Truck-Lite, says the number one advantage of LEDs is that “they are far more resistant to vibration than incandescents.” Substituting a solid material for a wire that’s soft because it’s white hot adds so much to the life of a lamp that Van Riper adds, “In all the years of testing LEDs in truck cabs, we’re never had one fail.”

Van Riper says LEDs are also monochromatic, which means they produce only one color. This means they can produce a pure red or yellow light and use a clear lens. Incandescents produce white light, which is then converted to the needed color via a lens. Most of the light energy, thus, is thrown away as heat. That’s just one reason they use a lot less power. LED stop lamps also reach peak brightness more quickly when you brake, giving the driver behind more time to react.

It’s easy to make the switch. Truck-Lite provided complete information to show how their LEDs can be substituted for existing incandescents. Many other brands of lamps can be converted similarly. Contact your parts distributor or the manufacturer for details.


1. You’ll need to purchase the new lamp and Truck-Lite Fit N’ Forget It adapter pigtail and some anti-corrosion compound like Truck-Lite’s NYK. You should also purchase a new grommet to mount the lamp in the bumper unless you know the one surrounding the lamp you’re replacing is in practically new condition.



2. This is how the red stop lights and the white backup light look from the rear of the tractor. We’ll be replacing the red stop lamp on the left.






3. Work from in front of the rear bumper. From this position, the lamp we’ll be replacing is the one on the lower right.





4. Gently work the connector plug off the connection on the lamp and allow it to hang loose.





5. Next, pull the lamp rearward out of its rubber grommet and remove it.





6. The grommet sits inside a large hole machined into the rear bumper. It is retained by a groove in its outer diameter. The grommet retains the lamp through friction, and also serves to cushion it from shock. Inspect the grommet carefully for any signs of weathering or heat cracking or other damage. Van Riper says, “Grommets tend to deteriorate over time and the fit, appearance and performance of the new lamp will be enhanced with a new grommet.”

Unless the grommet looks to be in new condition, replace it by carefully prying it out of the bumper. Gently work the new grommet through the hole until the metal of the bumper fits into the groove all around. You may want to wet the outside diameter of the grommet first to make it easier to work into the bumper hole.



7. Apply some anti-corrosion compound into the connection of the new lamp. “Apply only a small amount of NYK,” Van Riper says. The plug and lamp seal tightly, and too much compound trapped inside will keep the plug from going on all the way and locking properly.

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