Peterbilt 357/378 LED Headlights

Frequently Asked Questions About Peterbilt 357/378 LED Headlights

Will these LED headlights fit my specific year Peterbilt 357 or 378?

Our LED headlights are designed to fit Peterbilt 357 models from 1987-2007 and Peterbilt 378 models from 1986-2007. These are direct replacements for the standard 7-inch round sealed beam headlights. However, if your truck has been modified with custom headlight buckets or non-standard mounting hardware, you may need to verify measurements before ordering. The standard mounting depth required is 3.5 inches behind the headlight ring.

Do I need any special wiring adapters or will these plug directly into my existing harness?

Most of our LED headlights come with H4 plug-and-play connectors that work with the factory wiring harness. However, some older Peterbilt models (pre-1990) may have sealed beam connectors that require an H4 to sealed beam adapter, which we sell separately. No cutting or splicing is required. If your truck has been previously modified with aftermarket lighting, double-check your connector type before ordering.

How difficult is the installation and what tools do I need?

Installation typically takes 30-45 minutes per side and requires basic hand tools: a Phillips screwdriver, flathead screwdriver, and possibly a 10mm socket for some mounting rings. You'll need to remove the headlight trim ring, disconnect the old bulb, connect the new LED unit, and reassemble. The most common challenge is dealing with corroded screws on older trucks - having penetrating oil on hand is recommended. No aiming adjustment is usually needed as these maintain the factory beam pattern.

What's the actual brightness difference compared to stock halogen lights?

Our LED headlights typically produce 3,000-4,500 lumens per light compared to 1,000-1,500 lumens from standard halogen sealed beams. This translates to approximately 200-300% more usable light on the road. The LED units also provide a cleaner white light (5000K-6000K color temperature) versus the yellowish halogen output, improving visibility in rain and fog. DOT-approved models ensure the beam pattern meets legal requirements without blinding oncoming traffic.

How long do these LED headlights actually last and what's covered under warranty?

Quality LED headlights are rated for 30,000-50,000 hours of operation, compared to 500-1,000 hours for standard halogens. In real-world trucking applications, this typically means 5-10 years of service life. Most units carry a 2-3 year warranty covering defects and premature failure. The aluminum housing and polycarbonate lens are built to withstand road vibration, but damage from rocks or accidents isn't covered. Keep your receipt and register your purchase for warranty claims.