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TECHNICAL INFORMATION
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Customer Service: 800-562-5012 / Technical Support: 888-562-5012
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TEC
What lights do I need?
Look at wall charts. Check the requirements on our website (www.truck-lite.com). Call Tech Support (888/562-5012). Note
that states cannot require anything different than what is in "108." However, states can add regulations. Contact the Truck-
Lite lab for special situations.
"The vehicle has everything needed for 108, but the State Police gave me a ticket anyway."
States can regulate anything not covered by "108." For example, any accessory lights or lights in addition to those in
"108." Generally the problem is in these areas. Sometimes they make a mistake. In that case, Truck-Lite’s lab can often
write a letter to clarify the issue.
What are combination marker/clearance lamps,
and how do I mount them?
It is one light doing the work of two. It must be at a 45 degree angle (on corners) to be legal. It needs to be marked "PC" in
the lens code. If there is a question, contact the Truck-Lite laboratory.
How hard should I tighten down (torque) plastic lights or devices?
Overtorquing will generally cause cracking or distortion. Use the torque spec provided by the manufacturer. A marker lamp
will generally be in the neighborhood of 8 to 20 inch lbs.. The "rule of thumb" is to use the minimum torque necessary to
hold the device.
Are heavy-duty harnesses worth the extra cost?
Heavy duty harnesses provide an independent (secure) ground, less voltage drop and are completely sealed to avoid
corrosion.
What is the "12 Square Inch rule?
On December 1, 1991, the National Highway Traffic Safety Administration (NHTSA) made effective the final ruling regarding
the "12 Square Inch Rule." This ruling requires that the total luminous lens area for a stop and turn lamp must not be less
than 75 centimeters squared (11.625 square inches) when used on vehicles over 80" wide. It must be noted that the reflex
reflector ring cannot be counted as square inch lens area. When the reflex ring is subtracted from the total 12 inch lens, it
leaves less than the 12 square inches required.
Is it illegal or non-compliant to use red or yellow LED lamps that have clear lenses, but
produce the same red or yellow light output?
No. There is nothing illegal or non-compliant with having red or yellow LEDs behind clear lenses. The effective color of
the light when illuminated is red or yellow, which are approved colors of SAE J578c requirements. Clear lenses are legally
approved for SAE J578c regulations as well. For a specific statement of the requirements, please review the NHTSA
regulations charts.
Frequently Asked Questions