Peterbilt 357/378 Frame Light Bars & Filler Panels

Frequently Asked Questions About Peterbilt 357/378 Frame Light Bars & Filler Panels

What are frame light bars and filler panels used for?

Frame light bars and filler panels mount along the truck's frame rail, typically between the cab and fuel tanks or along the rear of the frame, to hold marker, clearance, and accessory lighting while also closing gaps between components for a cleaner, finished look. They serve both a functional lighting purpose and a cosmetic role by covering exposed frame areas.

Will these panels fit my specific Peterbilt 357 or 378?

Fitment can vary depending on your truck's frame length, tank configuration, and model year, so it's important to check the listed specifications and part numbers against your VIN or existing panel dimensions before ordering. If you're unsure, reaching out to our sales team with your truck's details is the best way to confirm compatibility.

What materials and finishes are available?

These panels are commonly offered in stainless steel or aluminum, with finish options ranging from brushed or polished stainless to painted or plain aluminum. Stainless steel tends to hold up well against corrosion and is easier to keep looking clean, while aluminum offers a lighter-weight alternative.

Do the light bars come pre-drilled for lights, and what bulbs or lights do they use?

Most light bars are pre-drilled to accept standard round or oval marker lights, but hole spacing and light size can differ between products, so check the listing details for exact specs. Lights themselves are often sold separately, so confirm whether your chosen panel includes lights or requires you to purchase them separately.

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

Installation generally involves removing the factory panel or trim piece and bolting the new one into the existing mounting holes, making it a manageable job for most owners or shops with basic tools. If lights aren't pre-wired, you'll also need to run wiring to your truck's marker light circuit, so having some basic electrical know-how or a wiring harness on hand will make the job easier.