What TLL9RK Actually Is
TLL9RK is a right-side trailer tail light kit built around a DOT-certified LED lamp running stop, turn and tail on a 12V circuit. The reflex reflector is molded into the lens, so one unit covers the rear lighting and reflector requirement on that corner instead of running a separate stick-on reflector.
The housing is sealed to IP67 and rated for submersible service, which is what you want on a boat trailer that gets backed down a ramp. Solid-state LEDs mean there is no filament to shake apart on washboard gravel, and current draw is a fraction of an incandescent lamp on the same circuit.
The kit is intended for trailers under 80 inches wide, where the code requirement is stop-turn-tail plus reflector rather than the wider-trailer requirement for additional clearance and identification lamps. Bulbs are included and the finish is smooth so road film and salt spray wipe off instead of packing into ribbing.
Why These Numbers Cross
Optronics TL38RB and STL39RB show up as the common interchange numbers for TLL9RK. All three describe the same functional lamp on the right side of the trailer: 12V stop-turn-tail LED, sealed housing, integrated reflector, sized for the standard trailer light pocket. The differences between the source numbers are usually kit content and mounting hardware, not the lamp function itself.
Trailer lighting settled on a small set of industry-standard footprints years ago — 4-inch round and 6-inch oval being the two you see most. That is why an aftermarket kit can cross to more than one brand number: the pocket, the grommet and the three-wire pattern are shared across the industry, so the lamp interchanges as long as the mounting style matches.
Treat the cross as a starting point, not a guarantee. Pull the old lamp, read the number stamped on the back or the lens, and measure the opening in the trailer body before you order. If the trailer has been rebuilt or the light pockets were cut by hand, the number on the paperwork will not always match what is bolted on.
Checks Before You Order
Measure trailer width first. This kit is for trailers under 80 inches. If you are over that, the lighting requirement changes and you need a different setup, so confirm the measurement across the widest point of the body or fender, not the axle.
Then confirm the mounting style — round or oval — and whether the trailer uses a grommet-mount pocket or a surface-mount bracket. Check the wiring too: count the wires at the old lamp and look at how the ground is picked up. Some trailers ground through the frame, others run a dedicated ground wire back to the connector, and that changes what you land on.
TLL9RK Cross-Reference & Interchange Numbers
These manufacturer and aftermarket numbers commonly cross-reference to TLL9RK. 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 |
|---|---|
| Optronics | TL38RB, STL39RB |
Frequently asked questions
Will TLL9RK replace an Optronics TL38RB or STL39RB?
Those are the listed interchange numbers, and all three cover a right-side 12V stop-turn-tail LED with integrated reflector for trailers under 80 inches. Verify by reading the number on the old lamp and measuring the mounting opening. Cross-reference identifies the part; the old part and your mounting confirm it fits.
Does this kit include the left side too?
No. TLL9RK is the right-side kit only. If both corners are damaged or you are converting the trailer from incandescent to LED, order the matching left-side unit as well so the two lamps look and behave the same. Mixing an LED on one side with an incandescent on the other can cause uneven brightness and flasher issues.
Can it go underwater on a boat trailer?
The housing is sealed to IP67 and rated for submersible service, which is the standard for lamps mounted in a boat trailer wheel well. Still seal the wire splices with heat-shrink butt connectors and dielectric grease at the connector — most ramp-service failures start at the wiring, not the lamp body.
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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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