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Optronics Trailer Tail Light - Stop, Turn, Tail - Incandescent - Round - Red Lens

Optronics Trailer Tail Light - Stop, Turn, Tail - Incandescent - Round - Red Lens

Item # ST40RB
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Optronics Trailer Tail Light - Stop, Turn, Tail - Incandescent - Round - Red Lens Round ST40RB
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5-3/8" Diameter round. Incandescent trailer light provides stop, turn, and tail signal. Shock-proof socket protects bulb against damage. Durable steel housing. Flush mount to trailer - hardware not included. 2-Wire design. (1) 2057 bulb. Lowest Prices for the best trailer lights from Optronics. Optronics Trailer Tail Light - Stop, Turn, Tail - Incandescent - Round - Red Lens part number ST40RB can be ordered online at etrailer.com or call 800-298-8924 for expert service.
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  • Reviews (97)
  • Q & A (25)
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  • Why etrailer?

Optronics Trailer Lights - ST40RB

  • Tail Lights
  • Round
  • Incandescent Light
  • Red
  • Recessed Mount
  • 4-1/2 Inch Diameter
  • Non-Submersible Lights
  • Optronics
  • Stop/Turn/Tail

5-3/8" Diameter round. Incandescent trailer light provides stop, turn, and tail signal. Shock-proof socket protects bulb against damage. Durable steel housing. Flush mount to trailer - hardware not included. 2-Wire design. (1) 2057 bulb.


Features:

  • Round incandescent trailer light serves 3 functions
    • Stop, turn, and tail
  • Shock-proof socket protects bulb against damage
  • Incandescent 2057 bulb can be easily replaced
  • Durable steel housing
  • Red acrylic lens over bulb
  • Compatible with 12V DC systems
  • Flush mount to trailer with flange - hardware not included
    • Requires cutout
  • 2-Wire design includes power lead and ground wire


Specs:

  • Dimensions: 5-3/8" diameter x 1-9/16" thick
  • Bulb type: 2057
  • Power draw at 12.8V:
    • Stop/turn: 2.4 amps
    • Tail: 0.49 amps
  • 3-Year warranty


Manufacturer Cross Reference
Light will work as an exact replacement for:
Uni Bond # TL4300R
Truck Lite # 80334R
Grote # 50232
Peterson # 413/425

Optronics ST40 Series Tail Light Dimensions


ST40RB Optronics Trailer Tail Light - Stop, Turn, Tail - Incandescent - Round - Red Lens

Alternate part number: ST-40RB




California residents: click here



Customer Reviews

Optronics Trailer Tail Light - Stop, Turn, Tail - Incandescent - Round - Red Lens - ST40RB

Average Customer Rating:  4.6 out of 5 stars   (97 Customer Reviews)

5-3/8" Diameter round. Incandescent trailer light provides stop, turn, and tail signal. Shock-proof socket protects bulb against damage. Durable steel housing. Flush mount to trailer - hardware not included. 2-Wire design. (1) 2057 bulb.

- ST40RB
by:

Light worked really well, had to figure out the color scheme of the lights since mine were so old but it worked great. Thank you 851393



- ST40RB
by:

Great 820395



- ST40RB
by:

Lights work great, no issues. 803512



- ST40RB
by:

Ordered a pair of steal cased brake lights for a project of mine, very strongly built and a great illumination. Very pleased with the sales and service from the folks of Etrailer ! 800936



- ST40RB
by:

As Advertised good product. 783729



- ST40RB
by:

Flush mount stop/tail lights. Best price i could find for these lights. Lights appear to be well made. Fast shipping. Great customer service. 718894



- ST40RB
by:

Exact replacement and fast shipping, doesn't get better! 5 stars!! 706868



- ST40RB
by:

Exactly what was advertised. Fast shipping. Will gladly purchase from you again. 706568



- ST40RB
by:

Product arrived quickly and was what I needed.. customer service is excellent and intelligent..... 696254



- ST40RB
by:

Looks good. Had to add a ground wire. 694148



- ST40RB
by:

I purchased the Optronics Trailer Tail Light - Stop, Turn, Tail - Incandescent - Round - Red Lens for my camper. They were an exact match to the originals! Easy to order, great price, received quickly, easy to install, quality construction, just what I needed. Super service, I couldn't be more pleased or impressed with your company. A true pleasure doing business with you! 692186



- ST40RB
by:

Came on time..connected easily to the trailer..works fine. Will shop with you again. 683803



- ST40RB
by:

The product arrived fast, the online description matched perfectly to the parts received, I recommend it 679962



- ST40RB
by:

Didn't notice the snap ring. Very convenient if used on a trailer but not what i wanted for my golf cart. Although they did fit in it perfectly i won't use them on the cart. Trading them out with my car hauler. Same size. Nice lights though. 678654



- ST40RB
by:

The groove for the retaining ring is virtually nonexistent. Tap or jiggle it a little bit and the ring pops out and then the lens. I had to apply a couple dots of clear caulk around the lense and ring to keep them in place. But it works for a $5 taillight. 667376



- ST40RB
by:

Cheap crappy product 642183



- ST40RB
by:

Satisfied 642115



- ST40RB
by:

Perfect... Fast Service 641107



- ST40RB
by:

Fits well and works great. Wish there had been installation instructions regarding the wiring for us novices. 603994



- ST40RB
by:

fast shipping easy to navigate website 600915



- ST40RB
by:

The items I ordered arrived quickly and we're priced very affordable. 584306



- ST40RB
by:

I haven't installed it yet my product yet, but the Etrailer service was awesome. My product shipped and was at my house within a couple days. 582125



- ST40RB
by:

Thank you very much perfect fit just like it was made for it. Do you know how can find out more about this trailer? 568302


Comments
It looks like an old livestock or horse trailer. The stamp on the back that says longhorn trailer company in Wichita falls, Texas closed in 2014. They were open for 68 years so its hard to tell how old it is.
-- Heather A - 10/05/2018

44346

- ST40RB
by:

Super fast great product priced right! 560562



- ST40RB
by:

Haven't installed it yet BUT it looks like an exact match to the one that broke when I lost a tire! 528396


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Ask the Experts about this Optronics Trailer Lights

  • 4 Inch Round Trailer Tail Light Cutout Size
    The closest to 4 inch round lights we have is the Optronics LED Trailer Utility Light # BUL43CB or Trailer tail Light # STL55RB which are actually 4-5/16" diameter x 1-15/16" thick. These are designed to fit the Rubber Grommet for 4" Round Trailer Lights - PVC # A45GB which requires a 4-1/2 inch diameter cutout. You will also need wiring pigtail # A47PB. If you are interested in the Optronics Trailer Tail Light - Stop, Turn, Tail - Incandescent - Round - Red Lens # ST40RB you asked...
    view full answer...
  • With Trailer Connected Truck Reverse Lights and Trailer Brake Lights Are Not Working
    It sounds like you might have a few different issues going on here. First, we need to test the vehicle side 7-Way connector to make sure it is working properly. Use a circuit tester such as # PTW2991 to test the pins on the connector while someone sits in the truck and runs through the light functions. If something does not work then you will need to determine the problem. Check the trailer connector for corrosion inside and out. Corrosion can cause all sorts of issues, so can ground...
    view full answer...
  • Troubleshooting Running Lights Circuit on a Travel Trailer Tail Light Harness
    Since you have tested the 4-Way connector on your vehicle and it is working properly, it leads me to believe that the wiring of the lights is incorrect. You will want to make sure that the fuse for the running lights on the vehicle is not blown. It sounds to me like the lights you have only have two wires coming out of the back for wiring to the trailer connectors wiring. If this is the case then the red wire will connect to the yellow (left) and green (right) wires on the trailer lights....
    view full answer...
  • Replacement Lens for Grote 5023 and Truck-Lite Trailer Tail Lights
    I do have an option for you but as we do not carry the trailer tail lights that you have, we would not have the correct replacement lens for you. That said, I can only imagine you will have a hard time trying to find an exact replacement as replacement lenses for old trailer lights are pretty hard to come by. Therefore, I recommend you replace the entire light as this is really your best option, the Optronics Trailer Tail Light part # ST40RB is very cost effective and is easy to install...
    view full answer...
  • What are the Wire Functions on Trailer Tail Light # ST40RB
    Trailers have tail lights that have a combined brake and turn signal on the same circuit. For light # ST40RB as an example, the green wire carries right turn and brake lights. The brown wire is only running lights. It sounds like you attached the brown and yellow wires on the tail light to the brake and turn signal wire from the trailer connector. The trailer connector at the front of the trailer should have 4 wires coming out of the back of it. The covered pin is the ground wire. The...
    view full answer...
  • Power is Getting to Trailer Light but the Light Will Not Light Up
    There are a couple of things that you can check to see what the problem is with your trailer light. Since you mentioned that power is getting to the light it could be that the circuit is not being completed meaning a bad or weak ground connection. Light # ST40RB grounds through its mounting hardware. The attachment point must be clean and corrosion free. If there is anything between a light ground and the metal trailer frame or if the trailer has an aluminum frame, tilt bed, or folding...
    view full answer...
  • Looking for 2-1/2 to 3 Inch Clear Round Trailer Light
    It depends on what type of light you are looking for. If you want a tail light assembly then it would have to have a red reflector on it to be DOT approved. If you are looking for a utility light (white light) then we do have some available, # UCL60CB or # UCL50CB. As far as just a lens we have some clear ones but they are over 4 inches in diameter.
    view full answer...
  • How to Determine the Functions of the Trailer Wiring on a Triton Trailer
    Most likely the white is ground, the brown is tail lights, the green is right turn/brake and the red is left turn/brake, but since the colors are a little different than the standard I would recommend you wire the trailer by function instead of color. This way you will eliminate and guess work and you will know that your trailer is wired correctly. The easiest way to do this would be to get a car battery and use a jumper cable to put current on each wire to see what tail light functions...
    view full answer...
  • Magnetic Flat Towing Tow Bar Wiring Kit Flashes Both Turn Signals Instead of Just One
    On a 7-Way, just as a 4-Way, the turn signals and brake lights are combined on the same circuit on each side. So yellow is left turn and brake, green is right turn and brake, brown is running lights, and white is ground. Usually when there is a red wire it is brake lights. But on a combined system like this the brake lights should be combined with the turn signals. There could be a short that is causing both turn signals to activate at the same time. You will want to inspect the wiring...
    view full answer...
  • Troubleshooting the Brake Light Function of the Optronics Round Trailer Light part # ST40RB
    The Round Trailer Stop, Turn and Tail Light # ST40RB that you referenced grounds through the mounting hardware. A weak ground could definitely cause the brighter illumination of the # ST40RB to not function. I would make sure that this light is installed on a clean metal surface that touches the frame of your trailer. If not, you could run a jumper wire from the mounting hardware of the light to the frame of your trailer to improve the light's grounding. You could also test the assembly...
    view full answer...
  • Replacement Red and Clear Trailer Light Lenses for Peterson Lights
    We have a wide range of replacement trailer light lenses for Peterson and many other brands of popular trailer lighting. The linked page will let you select the shape of the lenses you need. If you know the brand of light you have, such as Peterson, you can also click on that filter to narrow the results shown. For examples, for a clear lens for a Peterson 413S stainless trailer tail light we have part # 414-15C. Part # 420-15 is a replacement red lens for a Peterson model 428S trailer...
    view full answer...
  • Power is Getting to the Trailer Lights But they Will Not Light Up
    Use your circuit tester to test the wiring directly at the back of the lights. If the power is not getting to that point then there is a wiring issue that you will need to track down and repair. If power is getting to the light and the light is not coming on then the issue is either a weak or bad ground or there is something wrong with the light. The ground needs to be attached to a clean and corrosion free bare metal surface. Try moving the ground to a different location or run a jumper...
    view full answer...
  • Reverse Lights Illuminate With Running Lights On In Vehicle
    If the reverse lights on the trailer are on while the running lights in the vehicle are activated you most likely have a short between the reverse light wire (usually purple) and the running light wire (usually brown) on the trailer. Therefore, you will need to trace each of these wires back from the trailer side connector to make sure they have not shorted out to one another. I also recommend that you check the pins inside the trailer side connector for corrosion. Please note, aluminum...
    view full answer...
  • Trailer Back-Up Alarm Sounding when Brakes are Applied
    The back up alarm feed should be tapped into your reverse lamp lead, it sounds as if it is wired incorrectly. Each turn/brake lamp can be wired in series with a feed from your junction box, with one feed for the drivers side and another for the passenger. The same goes for your running lamps. You would take the feed for the drivers side brake/directional lamp which is usually a yellow wire, and run it along the rear of the trailer, feeding each of the two directional/brake lamps as you...
    view full answer...
  • Which Wires Serve What Function on Optronics Light ST40RB
    The green wire is for the brakes and turn signals and the black wire is for the tail lights .
    view full answer...
  • Troubleshooting No Trailer Running Lights
    I would begin by testing the trailer connector on the vehicle to rule that out. Turn the headlights on, and use a circuit tester like part # 40376 to test the socket on the connector fed by the brown wire. If you are not getting a signal on this pin, you might have a blown fuse. Make sure the ground wire from the connector on the trailer is securely grounded to the trailer frame and that each lamp is grounded to the trailer frame either by an individual ground wire connected to the trailer...
    view full answer...
  • Trailer Clearance Lights Show Power but Some Will Not Light Up
    It is possible that the clearance lights are not working if you have a lot of clearance lights. This can overload the trailer wiring on the vehicle side and cause some of the lights not to work. You can check the amperage draw per clearance light by testing one at a time using a multimeter such as # BTMT15. Switching everything over to LEDs will be much better because they draw only a fraction of the power compared to incandescents. Another possibility is a poor ground connection. All...
    view full answer...
  • Trailer Running Lights Do Not Work Using Tail Light # ST40RB
    It does sound like a ground problem. Use a circuit tester such as # 40376 if you do not already have one to test the running light wire at the back of tail light # ST40RB. If there is no power at the running light wire then the issue is not at the light but further up on the trailer or tow vehicle. If there is power to the wire then the issue is most likely that the circuit is not being completed because of a bad ground. This tail light grounds through the mounting hardware so it will...
    view full answer...
  • How to Remove Tail Light That Has Rivets Holding the Grommet in Place
    It all depends on how the light installs. If it is like the Optronics part # ST45RB that installs with the grommet # A45GB then you should be able to remove it without removing the grommet. You may need access behind the light to do this though. If your tail light is more like the Optronics part # ST40RB though where the grommet is part of the light then you will need to remove the rivets by drilling them out and then use new rivets or even screws to install the new tail light (or the...
    view full answer...
  • Comparing Optronics # ST40RB and Optronics # STL003RFLB Trailer Lights
    Aside from the Optronics # ST40RB having an incandescent bulb and the Optronics # STL003RFLB being LED the only other big difference is that the first part grounds through the mounting hardware while the LED version grounds through a wire. This is why one unit has 2 wires and the other has 3. We have 2 pigtail options for the LED verison for you to use. Part # A45PB has the wires coming straight out of the plug while part # A47PB has a right angle for tight spacing where your lights...
    view full answer...
  • Wiring Instructions for Optronics 4-1/2 Inch Round Trailer Stop Turn and Tail Light # ST40RB
    Thanks again for ordering with etrailer.com, we appreciate your business. As for the ground, you are correct, the light housing on the Optronics 4-1/2 Inch Round Trailer Stop, Turn, and Tail Light, # ST40RB, doubles as the ground. Now for the green and black wire, the green wire is for the running light circuit and the black wire is for the turn signal and brake light circuit. I have attached a short installation video for you.
    view full answer...
  • Replacement LED Trailer Light to Reduce Power Draw
    The Optronics LED Trailer Light # STL42RB is not what I could call an exact replacement for the # ST40RB but for all purposes it will be what you're looking for. The # STL42RB is 1/8 inches larger in diameter and 3/8 inches deeper so at the most you may need to do a little filing to the opening for the light in your trailer to install it. The mounting flange is metal. There is also a Stainless Steel Trim Ring # A5TRSSB available. It does not include a gasket, however If you would...
    view full answer...
  • Installation of Tail Light Lens Using Retainer Snap Ring
    The Replacement Tail Light Lens # A40RB is not held on with screws. The outer bezel housing of the 4-1/2" Round Trailer Stop, Turn and Tail Light, Flange Mount, 3-Function # ST40RB for instance has the housing held by screws and the lens is held by the metal snap/retainer ring and indentation in the housing. That Replacement Retainer Ring # 410-21 is a separate item.
    view full answer...
  • Do Bulbs Come with Optronics Lights ST40RB, MC32RB, MC32AB
    Yes, the bulbs do come with the Optronics Lights # ST40RB, # MC32RB and # MC32AB. They are already installed in the lights assemblies so all you will need to do is wire up the assemblies and you will be good to go. I attached review videos for the # MC32RB and the # MC32AB for you to check out also.
    view full answer...
  • What is the Difference Between a Snap Ring and Retainer Ring for a Trailer Tail Light
    There really isn't a difference. Snap-ring and retaining ring such as # 410-21 are two names for the same thing. If your tail light looks like # ST40RB then use # A40SRB. But you mentioned that the light was 4 inches, which is what Peterson light # 429800 is. So for that light use # 410-21. Shipping can vary depending on the option you choose and where you live. So take a look at the link to the right that explains more about shipping and how to determine cost.
    view full answer...

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Info for this part was:

Expert Research:
Mike L
Expert Research:
Robert G
Expert Research:
Michael H
Expert Research:
Jameson C
Expert Research:
Adam R
Video by:
Kathleen M
Updated by:
Laura H
Updated by:
Brian T
Video Edited:
Dustin K
Installed by:
Cole B

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