What This Assembly Is
This is a complete passenger-side headlight assembly, not a bulb or a lens. It arrives as a sealed LED unit in a black housing, 12 volt, with the light source already installed. You unbolt the old corner, transfer nothing, and set the new one in place. Side designation is R, so confirm you are ordering the correct corner before you click.
The optics are a DOT/SAE compliant LED projector rather than a reflector housing with a halogen capsule. The cutoff is sharper, which matters at scale weight on a two-lane road at night. Beam aim still has to be set on the wall or on a machine after installation, same as any headlight swap. A new assembly does not aim itself.
Housing is IP67 sealed, so pressure washing the front clip and running through road spray will not pull moisture in the way a cracked halogen housing does. The harness side is plug-and-play on factory connectors with load resistors built in, so the dash should not throw a lamp-out fault after the swap.
Why These Numbers Cross
A6601405002 and A66-01405-005 are the same base casting and the same electrical layout written two different ways. The dashed version is how the number appears in Freightliner literature and on some housing tags; the run-together version is how it gets typed into parts systems and search bars. Different punctuation, same passenger-side LED corner.
FR-LITE601 is the FleetRun catalog number for the aftermarket equivalent. Aftermarket suppliers assign their own SKUs rather than reusing the truck maker's numbering, so the number looks nothing alike while the part interchanges. All of these numbers are listed here for identification only. PartStop LLC is not affiliated with, endorsed by, or authorized by any OEM manufacturer.
Cross-reference is a starting point, not a fitment promise. Cascadia front-end hardware changed across production, and the number molded or stickered on your old assembly is the fastest way to be sure. Pull the old unit, read the tag, or verify by VIN with your dealer before you order.
Check Before You Order
Confirm the side. This is the right, passenger-side unit. If you are replacing both corners after a front-end hit, you need the left assembly as a separate part number. Confirm your truck is running LED corners and not halogen, since the connector and mounting differ and a halogen truck will not take this unit as a straight swap.
Before you condemn the assembly, check the ground and the connector. Corroded pins and a chafed harness behind the bumper cause the same dim or dead low beam as a failed LED module. If one side is dead and the other works, swap-test the connector where you can reach it. If the housing is full of water or the lens is crazed, the assembly is done.
A6601405002 Cross-Reference & Interchange Numbers
These manufacturer and aftermarket numbers commonly cross-reference to A6601405002. Use them to identify the part — then confirm the exact fit by VIN or the number stamped on your old unit before you order. An interchange is a starting point, not a fitment guarantee.
| Brand / Line | Cross-Reference Numbers |
|---|---|
| FleetRun | FR-LITE601 |
| Freightliner | A66-01405-005 |
Frequently asked questions
Is A6601405002 the driver side or passenger side?
Passenger side. The side code on this assembly is R, meaning right-hand as you sit in the seat facing forward. If you need the driver corner, order the left assembly separately. Replacing only one side is fine electrically, but a new LED next to a sun-faded old lens will show an obvious brightness difference.
Does FR-LITE601 fit the same trucks as A66-01405-005?
They are listed as interchange for the same passenger-side Cascadia LED corner. FR-LITE601 is the aftermarket catalog number and A66-01405-005 is how the number reads in Freightliner literature. Use the number on your old assembly or your VIN to confirm before ordering, since front-end hardware varies across Cascadia production.
Do I need extra resistors or a wiring adapter?
No. The harness uses factory connectors and the load resistors are built into the assembly, so it plugs straight in without splicing. If you get a lamp-out warning after installation, check that the connector is fully latched and that the ground is clean before assuming the unit is bad.
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Run your VIN and we’ll match parts to your exact truck, or call the counter — a person who knows trucks verifies fitment by OEM number before the order ships. No wrong-box returns.
More cross-reference guides
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