See what our Experts say about this Optronics Trailer Lights

• 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.
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• 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 from...
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• 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...
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• 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 # PT89ZR. 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...
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• 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...
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• 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.
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• 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....
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• 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...
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• 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...
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• Recommended Round Trailer Tail Light With Bright White And Red Light Functions
  Hey Rob, The best option for both a red and clear lens that's going to produce a bright light is going to be the Fusion LED Hardwired Trailer Light # OPT97NR. It's the same 5-1/2" overall diameter as the # OPT89NR (BUL11CRMB) but it does have to be hardwired instead of using a plug-in connector. You can just cut of the old connector from your trailer's wiring and splice the new light in with some heat shrink butt connectors # DW05744-10.
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• 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...
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• 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...
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• 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 prefer...
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• 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...
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• 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.
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• 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...
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• 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.
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• 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.
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• Optronics Trailer Tail Light Replacement Lens Clip
  We do have a clip for the Optronics Trailer Lights, part # ST40RB. It is the Replacement Snap Ring, part # A40SRB. I've linked to a video installation of this light on a trailer.
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• 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...
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• 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 # PTW2993 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...
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• 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 .
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• 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...
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• 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...
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