Big Rig Basics

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.”

Partner Insights
Information to advance your business from industry suppliers
The ALL NEW Rand Tablet
Presented by Rand McNally

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.

8. Grab the adapter pigtail and plug it into the female connector on the back of the lamp. Note that the clip that locks it in place goes downward and that you need to push the plug into the lamp until the clip locks over the tab on the lamp.

9. Insert the lamp into the grommet from the rear. Then, working from behind the bumper, straighten the lamp so it sits straight inside the grommet.

10. Use a brush to clean the plug terminals on the wiring harness. Truck-Lite makes a special brush kit for this purpose. This will help ensure good electrical contact and prevent damage to the seals from grit.

11. Apply anti-corrosion compound to the terminals on the plug before connecting it.

12. Connect the plug from the wiring harness to the female connector on the adapter pigtail, and make sure it locks.

13. Use a cable tie to secure the wiring for the pigtail to the harness going to the tail and backup lamps.

14. Here is what the rear bumper lights will look like when the one on the driver’s side has been converted. The one on the other side will, of course, be converted in the same way.

For further information:


(800) 562-5012

Peterson Mfg.

(816) 765-2000

Grote Industries

(800) 628-0809

Super Bright LEDs, Inc.

(866) 590-3533

The Business Manual for Owner-Operators
Overdrive editors and ATBS present the industry’s best manual for prospective and committed owner-operators. You’ll find exceptional depth on many issues in the Partners in Business book, updated annually.
Partners in Business Issue Cover