Peterbilt 387 Frame Light Bars & Filler Panels

Frequently Asked Questions About Peterbilt 387 Frame Light Bars & Filler Panels

What are frame light bars and filler panels used for on a Peterbilt 387?

These components mount along the frame rail area between the cab and the front bumper or fuel tanks, filling the gap left by the truck's frame design. The filler panels provide a finished, streamlined look to the underside of the truck, while the light bars integrated into or mounted alongside them add auxiliary lighting such as marker lights, turn signals, or accent lighting.

Will a light bar or filler panel fit my specific Peterbilt 387 without modification?

Fit can vary depending on the model year, cab configuration, and whether your truck has factory or aftermarket bumpers and fairings already installed. Most panels are designed to bolt into existing frame mounting points on the 387, but we recommend checking the listed specifications and comparing them to your truck's setup before ordering to avoid unnecessary cutting or drilling.

What materials are these light bars and filler panels made from, and what finish options are available?

You will typically find these parts offered in stainless steel or aluminum. Stainless steel options often come in polished, brushed, or diamond plate finishes for durability and a bright, reflective look, while aluminum panels tend to be lighter weight and may be painted or left in a raw finish. The right choice depends on how much shine and maintenance you want versus weight savings.

How difficult is it to install a frame light bar or filler panel myself?

Installation difficulty depends on the specific panel and whether wiring is involved. Panels without lights generally bolt on using existing frame holes and basic hand tools. Light bars require running wiring to a power source and grounding it properly, so some electrical know-how or a wiring harness kit is helpful. Many installers can complete the job in a few hours in a home garage or shop setting.

Do the lights on these panels meet DOT requirements, and how do I wire them in properly?

Many light bars include DOT-approved marker or clearance lights, but it is important to verify the specific lighting configuration meets the requirements for your state and application before installation. When wiring, match the light bar's connections to your truck's existing marker or auxiliary light circuits, use proper grounding, and protect connections from road debris and moisture to prevent premature failure.