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Kenworth T680 Headlight Replacement: Complete Aftermarket Buying Guide (2026)
Last updated: June 2026 · 7 min read
The Kenworth T680 is one of North America's most popular Class 8 highway tractors, with hundreds of thousands on the road. When the headlight fails — and they do, especially the inboard turn signal LED clusters — Kenworth dealership pricing is brutal: $850-$1,400 per assembly. Quality aftermarket alternatives run $250-$550, with the same DOT-approved fitment.
This guide explains exactly what to look for when buying an aftermarket T680 headlight, how to verify the right fitment for your year, and the cross-reference numbers you need to confirm the aftermarket supplier has the correct part.
T680 headlight types by year
The T680 has run two distinct headlight designs since its launch:
- Classic T680 (2012-2021) — Halogen low/high beam assembly with an LED daytime running light strip; an LED DRL-style assembly was also offered
- T680 Next Gen (2022+) — Full LED assembly with redesigned bezel and integrated turn signal, using the P54-6157-100 housing family
Critical: aftermarket headlights are generation-specific. A 2017 classic T680 headlight will NOT fit a 2023 T680 Next Gen even though both are "T680." Verify your truck's exact build year before ordering.
Kenworth T680 headlight part numbers
Use these cross-references to verify your aftermarket supplier has the correct part:
| T680 Generation | Headlight family / cross-reference |
|---|---|
| Classic T680 (2012-2021) | P54-6164-100 (halogen assembly); P54-6103-11000 (LED DRL version) |
| T680 Next Gen (2022+) | P54-6157-100 |
Driver (LH) and passenger (RH) units are mirror-image — always order by side. Quality aftermarket suppliers list these cross-references in their product descriptions. If the supplier doesn't list them, they may not have the right part.
For the Next Gen T680, Evertrust stocks the P54-6157-100 assembly in standard chrome ($399.99 CAD) and a Next Gen LED black-housing version ($549.99 CAD). Running T880s in the same fleet? The T880 uses its own headlight family (P54-6165-100) — see the T880 headlight assembly — and the two do not interchange.
What to look for in an aftermarket T680 headlight
- DOT and SAE compliance markings — Required for road-legal use
- Polycarbonate (not glass) lens — More impact-resistant on highway debris
- Sealed housing with integrated weather seal — Prevents moisture intrusion (the #1 failure mode for T680 headlights)
- Direct-fit mounting tabs — Should bolt to OEM mounting points without modification
- 1-year warranty or longer — Anything shorter signals lower-tier quality
- Cross-reference numbers listed — As shown above
Pricing reality: aftermarket vs Kenworth dealer
| Source | Classic T680 (each) | Next Gen 2022+ (each) |
|---|---|---|
| Kenworth Dealer (OEM) | $850-$1,000 | $1,200-$1,400 |
| Quality Aftermarket | $250-$450 | $399.99-$549.99 CAD (Evertrust) |
| Typical savings per side | 60-70% | 55-70% |
Installation tips
T680 headlight replacement is a 30-45 minute job for most users with basic mechanical experience:
- Disconnect battery (yes, actually do this — there's high-current LED circuitry)
- Remove the front grille (usually 4-6 push-pin clips)
- Disconnect the electrical harness from the existing headlight (typically a 6-pin or 8-pin connector)
- Remove the 4 mounting bolts (10mm or 13mm depending on year)
- Pull the old assembly forward and out
- Install the aftermarket assembly using the same mounting holes
- Reconnect the harness — pin layout should be identical to OEM if you bought a quality part
- Reinstall grille
- Reconnect battery and test all functions: low beam, high beam, daytime running, turn signal
Common installation issues to watch for
- Wiring connector doesn't match — Quality aftermarket parts will match the OEM connector pinout. If yours doesn't, you bought a part for a different generation.
- Headlight aim is off — All headlights need vertical aim adjustment after install. Use the adjustment screws on the back of the housing.
- One side works, other doesn't — Likely a wiring connector issue, not a defective headlight. Inspect the harness connector for corrosion.
- Daytime running lights don't work — Check the dedicated DRL fuse. Aftermarket parts use the same fuse circuit as OEM.
Frequently Asked Questions
Are aftermarket Kenworth T680 headlights as bright as OEM?
Quality aftermarket T680 headlights match OEM lumen output specifications. LED versions of aftermarket T680 headlights typically produce 4,000-5,500 lumens per side, equivalent to OEM LED ratings. Cheap aftermarket parts may underperform.
Will an aftermarket T680 headlight pass DOT inspection?
Yes, as long as it carries the DOT marking and is properly aimed. Quality aftermarket T680 headlights meet FMVSS 108 standards required for DOT inspection.
Can I upgrade from halogen to LED on a classic (2012-2021) T680?
Yes. LED-style assemblies are made for the classic T680 platform and use the same mounting points. The brightness improvement is significant. Cost is typically $350-$550 per side; contact our parts team for current availability on classic T680 LED units.
What's the difference between SAE and DOT approval?
SAE (Society of Automotive Engineers) sets the technical standard. DOT (US Department of Transportation) is the regulatory approval. A part with both markings has been tested to SAE standards and approved for road use in the US.
How do I know if my T680 has halogen or LED OEM headlights?
Classic T680s (2012-2021) came with halogen low/high beams plus an LED daytime running light strip. Next Gen T680s (2022+) came with full LED. If your existing headlights have visible bulbs through the lens, you have halogen. If the lens is uniformly illuminated, you have LED.
Can both Driver and Passenger side use the same headlight?
No. Driver (LH) and Passenger (RH) T680 headlights are mirror-image designs and NOT interchangeable. Always order by side.
Bottom line
The Kenworth T680 headlight is one of the highest-savings aftermarket purchases you can make: typically 55-70% per side under OEM dealership pricing, with no functional compromise when buying from a quality supplier. Verify your generation (classic vs Next Gen), choose a supplier that lists the cross-reference numbers, and you'll get a 30-45 minute install that pays for itself the first time. Browse the full Kenworth parts collection or all truck headlights at Evertrust.