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

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

Part Number: ST45RB
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$5.34
Retail:$8.01
You Save: 33%
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4-1/4" Diameter round. Waterproof trailer light functions as a stop, tail, and turn signal light when properly mounted. Shock-proof socket protects incandescent bulb. Flush mount with grommet (sold separately). Accepts 3-prong plug. Great Prices for the best trailer lights from Optronics. Optronics Trailer Tail Light - Stop, Turn, Tail - Submersible - Incandescent - Round - Red Lens part number ST45RB can be ordered online at etrailer.com or call 1-800-940-8924 for expert service.
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Optronics Trailer Lights - ST45RB

Highlights

  • One Light, 3 Functions: Works as stop, tail, and turn signal for simple trailer lighting.
  • Reliable In Any Weather: Sonically sealed housing keeps water out for submersible use.
  • Durable Build: Shock-proof socket and polycarbonate lens protect the bulb from damage.
  • Easy Plug Connection: Accepts standard 3-prong plug for quick wiring to 12 V systems.
  • Fits Right In: Recessed mount installs with grommet #A45GB (sold separately).
  • Road Legal: DOT-compliant design meets required lighting standards.

Features to know about

Reliable Stop, Turn, and Tail Lighting: 3-Function Red Round Light

When you need dependable lighting that covers all the basics, this 4-1/4" round red light does it all. It works as a stop, tail, and turn signal when properly mounted, giving you everything you need for clear communication on the road. At 12.8V, it draws 2.4 amps for stop/turn and 0.49 amps for tail, keeping things efficient while still bright enough to stand out. It’s DOT compliant and ready to install where you need solid visibility day or night.

Optronics ST45RB round red incandescent trailer tail light with sealed waterproof housing for stop, turn, and tail functions.

Keeping Water Out: Sonically Sealed and Submersible

If your trailer ever hits the water, this light doesn’t flinch. The housing and red lens are sonically sealed into a single waterproof unit, so water can’t get inside to damage the bulb or socket. That sealed construction makes it ideal for boat trailers or any setup that sees rain or road spray. You get long-term reliability without having to open or reseal anything after every trip.

Built Tough for the Road: Shock-Proof Socket and Polycarbonate Housing

Rough roads or vibration won’t knock this light out. The shock-proof socket protects the incandescent bulb from impact, while the durable polycarbonate lens and housing resist cracks and wear. Whether it’s dust, bumps, or weather changes, this light is made to handle it without losing performance or clarity.

Clean, Flush Fit: Recessed Mount with 3-Prong Plug Connection

A clean look matters just as much as a secure mount. This recessed-mount design fits smoothly into a grommet (part # A45GB – sold separately) for a flush finish that stays tight even on the move. The back accepts an industry-standard 3-prong plug like part # A45PB or # A47PB (both sold separately) for a quick hookup—white for ground, black for tail, red for brake and turn. Once seated, the light stays locked in place until you’re ready to remove it.

Recessed-mount trailer light shown installed through a grommet with flush fit against trailer surface.

Specs

Dimensions

  • Overall dimensions: 4-1/4" diameter x 2-1/16" thick

Electrical

  • Power draw at 12.8V (Stop/turn): 2.4 amps
  • Power draw at 12.8V (Tail): 0.49 amps

Warranty

  • Warranty: 3-Year warranty

ST45RB Optronics Trailer Tail Light - Stop, Turn, Tail - Waterproof - Incandescent - 1 Bulb - Round - Red Lens

Alternate part number: ST-45RB





Customer Satisfaction Score:

Ratings & Reviews

4.8

2624 reviews
5 Stars
(2344)
4 Stars
(199)
3 Stars
(42)
2 Stars
(12)
1 Star
(27)
Review sort icon
4-1/4" Diameter round. Waterproof trailer light functions as a stop, tail, and turn signal light when properly mounted. Shock-proof socket protects incandescent bulb. Flush mount with grommet (sold separately). Accepts 3-prong plug.

by:

Fit and worked perfect! Came days earlier then tracking said. Great service and price! You know I will order from etrailer again!!



by:

super fast shipping, great prices, best place for shopping for parts for your trailer, I have used them several times and always been very satisfied with fast shipping and the products I have bought!!! Right on you guys!!! The best!!!



by:

It's round, it's red, it fits in the same spot the old one did, and the price is right. The actual diameter is around 4 5/16". This is the normal standard light that fits into the black rubber ring.



by:

Great customer service & timely response to my questions. I will use Etrailer again for all trailer lighting needs.



by:

The product was all I could hope for and the service from etrailer was superb. I placed an online order for one bulb and then decided the next day to change to two and called them. No problem they updated the order and I received both bulbs in three days. This is the first review I have ever written but the price and service deserve to be noted



by:

I am a new RV owner, and discovered 1 taillight not working on recently purchased dolly trailer. After finding your web-site in magazine, and ordering replacement lens, was pleasantly surprised on the quick response and delivery of replacement.



by:

Just got the camper home from a work trip. ordere before I finished the job, the wife brought them to me
fast delivery very good price.
couldnt find them local
I got a pair of nerf bars s.s./w lights early summer
Nice Very Nice also had fast shipment on those
thats why I came back. Very good vendor
Thanks Roy



by:

I have used etrailer before to fix lights on my old horse trailer. Info on the website gave me confidence I was ordering the right thing and the light came quickly and was exactly what I needed



by:

I looked in all the local auto supply stores for this unit with no luck. I didn't even know what it was called, but I found it on etrailer.com in no time at all. Shipping was fast and it was exactly what I needed.



by:

the lights that i ordered require a plug to connect them. nothing in the advertisement let me know i needed the plug so here i am out the cost of the lights and still cannot finish my trailer. not worth returning and i was running out of time, so i went to the local retailer and bought a complete set. i have had great luck with etrailer in the past, but i guess this deal was just too good to be true. threw them in the trash.



by:

I ordered new lights for my horse trailer. They are a perfect match, great price and arrived in 2 days via USPS at no charge. This was a great experience and I would reccomend etrailer to anyone needing parts for their trailers.
Good job guys!



by:

etrailer is the best online source for RV related parts. Can't beat their prices and service. The tail lights I got are perfect, well packaged, promptly shipped. I will always go to etrailer for RV parts.



by:

etrailer rocks !!
Quick delivery, product
exactly what I expected. Could not have been better.
Taillight for a pu truck utility bed, unable to talk with the parts department of the manufacturer who is relatively local, I guess they must be VERY busy, just googled the part # off the old unit and etrailer had it listed - bada bing - new unit at the shop in two days!! standard delivery. Will always look here first for parts.



by:

I was able to find the correct light online from the many you make. Shipping was fast and accurate. Five stars.

Thomas C. profile picture

Thomas C.

3/21/2022

The problem was not the light, but something in the electronics. I have no report on the light except it worked when I tested it.



by:

Product arrived on time - just as described & exactly what we needed. Great price for both the product & shipping.

Rayshell profile picture

Rayshell

7/9/2020

The product worked great, but I cannot say how it is after a year, as I sold the trailer that I put them on. I do know they were exactly as expected - good product - &amp I have since recommended etrailer.com to others.



by:

we bought an odd brand and older horse trailer and it had a tail light out. figured we would never find a replacement. I googled the name and etrailer popped up. the photos of the light, how it plugged in, what models it was compatible with etc, made it so simple for this 68 yr old non mechanical woman to find the right light. and the price was amazingly low. So, yes, I am very pleased and would recommend them to everyone!!



by:

I am very happy with every part of my experience buying from etrailer.com. The customer service was excellent, the product was perfect and I could not find anything like it locally. I highly recommend this company. Best of all the price was far lower than anywhere else on the internet! Oh one more thing. They even hade demo videos of the product so I could see it in action! Icing on the cake! Thanks etrailer.



by:

We had a horrible hail storm and it completely wrecked our new travel trailer. We could live with the hail damage until we could get it in for repair but what we couldn't live w/o was the tail light. I drove all the way down to the place I bought the trailer & they said they would order it for me. I asked how long? he said 'a week or two'. I said I needed it in a week because we were camping again the next weekend. Come Tuesday, I called & he said "o...I need to call the manufacturer" I knew at that point I could not rely on the parts department. I got on-line & found the exact light I needed. The pictures front & side helped a lot because there are so many lights to choose from....I paid for 2 day shipping & it was here before our camp trip...Very fast reliable service. Thats what customer service should be. It fit perfectly & worked properly.
Thanks so much! will use this company again in the future if needed!



by:

This taillight was very difficult to find - it went on a tow dolly that I tow behind my motorhome. etrailer got it to me on time for a tour of the National Parks in Utah.
It was difficult to install in the rubber grommet but once installed worked well the entire trip from GA and back! etrailer solved my problem and expeditiously!



by:

For the price I can hardly complain, but one of the two already lost it's parking/running light 2-3 months ago, and they've been installed less than a year. I use my lights maybe 10 min/day, only on early mornings on the way to work. I've also used the Peterson brand lights, but after replacing those multiple times for the brake lamps going out I decided I might as well try something cheaper if I was only going to get junk anyways. I guess I'll try LEDs next.



by:

Hi guys,
I'm usually the one answering
reviews
These guys are great! My client emailed the link & told me to order these for our horse trailers.
They've held up, to the point, we're not even close to needing to replace them.
We haul quite a bit. These lights have been tried & true, day & night.
When you're hauling a lot of livestock, you want people that have no clue what that entails, to see your lights well before they get near your livestock ; these lights do the job perfect!
We've outfitted 3 separate trailers with this company. We restored wires, lights, & pretty much everything along those lines ;from a 2 horse, to a large stock, & a gooseneck. All the parts come quickly, are all there, & work & fit great. What more can you ask for?!



by:

Product seemed to work very good, but I was unable to get it mounted on my trailer. I must have not ordered the right light or extra materials for mounting. Other than that, good product.

Patrick B. profile picture

Patrick B.

3/15/2013

There is a grommet listed in the related products section on the right side of this page. The grommet will be needed if you do not already have one or the old one is no longer usable.There is a bracket also available if this light is not going into a pre-existing mounting hole.



by:

Optronics ST45RB is perfrect replacement for GLO-BRITE 9541.



by:

This is a great looking classic trailer brake/turn light, which I used on my homebuilt woody teardrop. The lamp is quick and easy to change . . just pop it out from the base, unplug it, and plug in the new one. Etrailer, as always, does a great job providing all the parts a builder needs!



by:

Your service was excellent. The trailer light I needed was well described at your website. The ordering process was easy. You sent an email notice that the order was processed and shipped on the same day - wow. It arrived quickly and is now installed. It works perfectly as expected.
Much appreciated...

GZ Westcliffe, Colorado

Gary Z. profile picture

Gary Z.

4/2/2018

Thanks for your follow up. I appreciate dealing with a customer - concerned company such as yours. Running a ranch, I do have an assortment of old trailers which from time to time need replacement parts.You will alway have my business as meager as it is.The product is fine…Thanks, and best wishes for your business success.


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See what our Experts say about this Optronics Trailer Lights

  • Troubleshooting Trailer Taillights Where Only One Side of Trailer Lights Work
    First thing you should do at this point is test the 4-way of the wiring harness with a circuit tester part # PTW2993 for voltage on all of the right pins when the taillight signals are being applied. Just like in the video I attached. If the voltage checks out there but the trailer lights still don't function right then the problem is on the trailer wiring. That would mean that problem is either due to a ground issue or a short issue. Make sure that the trailer side connector are clean...
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  • Installing New Trailer Lights and Wiring on a Horse Trailer
    There isn't a kit available for what you are looking for, but you can still piece everything together. For grommets to use with the # ST45RB you would want the part # A45GB and then for a pigtail you would want the part # A45PB. Often times, people will run the wires from a 7-way such as yours to a junction box like part # 38656. From there, they will run the standard wire colors to the trailer lights, brakes and battery. I have attached a photo that shows how this setup works in the...
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  • 2 and 4 Inch Diameter Trailer Lights, Grommets, and Harnesses
    I will be happy to help and give you some options. For 2 inch diameter red lights we have several options: # MC53RB (use grommet # A54GB and harness # A46PB) # MCL50RB (use grommet # A54GB and harness # A46PB) # MCL55RB (use grommet # A54GB and harness # A46PB) # MCL55R1224B (use grommet # A54GB and harness # A46PB) All in one option # MCL-50CRK # MCL155RB (use grommet # A54GB and harness # A46PB) For 2 inch diameter amber lights we also have several options: # MC53AB (use grommet #...
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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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  • Replacement LED Trailer Tail Lights for a 2005 Gulfstream BT Cruiser
    Optronics trailer tail light # ST45RB is potentially a fit for your trailer if the existing lights are one of the following: Uni Bond # SE4000R Wesbar # 423541 Truck Lite # 40282R/40202R Grote # 52922 Peterson # 426R Bargman # 40-01-001 This information is likely on the light housing somewhere on your existing lights. The 2 knobs on the back are not an issue since this light would mount in a hole in the trailer or in mounting bracket # BK45BB both using grommet # A45GB. If you are not...
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  • Troubleshooting Stop/Turn Signal of a Optronics Light part # ST45RB on a Trailer
    It sounds like the problem is in the wiring. If your light is a dual intensity light and both intensities are working with the running lights and brighter with the brake lights then the problem lies in the turn signal circuit most likely on your vehicle. You might test the trailer connector on your tow vehicle with a circuit tester like our part # PTW2993 like the video I attached shows to determine if the wiring of your vehicle is good. If the problem is in the vehicle wiring you will...
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  • Adding Lights to a Kuat Sherpa 2.0 Bike Rack on a 2015 Land Rover Evoque
    There isn't anything specifically designed for lighting on a bike rack so you're going to have to be a little creative here. Since the Kuat Sherpa 2.0 # SH22G is aluminum and you don't want to drill into it (Understandably so) you'll need to find a way to mount lights to it. Zip ties, like you mentioned, are going to be your best option. Tying a light like # ST45RB would be difficult to find a surface but might work. You'll also need a 3-wire connector # A45PB per light. Then you'll...
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  • What Causes Dim Brake Lights on Yakima Rack and Roll Trailer
    With a trailer that is made of aluminum, you can experience grounding issues. Since you indicated that the light appears to work for the functions, but is dim when applying the brakes, I think this may be the problem. Due to vibration when in use, the wires can become loose, causing varied issues. I would first make sure all of the wire connections are secure on the trailer. You might want to check the ground wire connections on the trailer. Make certain the ground wire (usually white)...
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  • Replacement 4 Inch by 2 Inch Round Tail Light for a 2006 Damon Intruder RV
    The closest match we have to your existing Glo-Brite taillight is the Sealed, 4 inch Round LED Trailer Stop, Turn and Tail Light, Flush Mount, 3-Function, 12 Super Diode, # STL23R-24B. It measures 4 inches in diameter and 1-15/16 inches deep. To install this light, you would also need Rubber Grommet for 4 inch Round Trailer Tail Lights, # A45GB, and Straight 3-Wire Pigtail for Sealed Trailer Stop, Turn and Tail Lights, # A45PB. Since this light is an LED, if you determine that it is the...
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  • Replacement Round 4-1/4 Inch Grommet Mount Trailer Stop/Turn/Brake Lamps
    The closest lamp we offer to what you describe would be the Optronics # ST45RB. The lamp measures 4-1/4 inches in diameter at its largest, and the lamp installs into a 4-1/2 inch rough opening using the rubber grommet which is available separately as part # A45GB. If the 4.25 inch mounting diameter you refer to represents the diameter of the rough opening that the lamp installs in, this lamp will be a bit too large so you'd need to either enlarge the hole by 1/4 of an inch. The 3 pin plug...
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  • How Does Trailer Light # ST45RB Mount into Mounting Bracket # BK45BB
    I went out to the warehouse and pulled Optronics Trailer Light, # ST45RB. First, you will need to place the Rubber Grommet, # A45GB, into the mounting bracket, # BK45BB. Next, you will need to press the light until it is seated all the way in the bracket. This last step actually takes some strength as the light is held in place by the grommet. I had to use some lubricate to get the light to seat all the way in the mounting bracket. Once in place, the light will not come out unless it is...
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  • Can Bulb be Replaced on Optronics Trailer Tail Light # ST45RB
    I spoke with my contact at Optronics and he said that the Trailer Tail Light # ST45RB is a sonically sealed complete unit and the bulb cannot actually be replaced by itself. If the bulb goes out a new # ST45RB will be needed to replace it. I have attached a short video demonstration on this light that you can also check out.
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  • Replacement Trailer Lights for Truck-Lite Products
    Part 40282R3 refers to a Truck-Lite brand round red-lens light. We have the Optronics stop/turn/tail light # ST45RB which is a direct replacement. This light uses a 3-prong plug # A45PB and can mount using grommet # A45GB. Part 50-19200Y3 refers to a Truck-Lite brand rectangular amber clearance light. As a direct replacement we have Optronics # MC65AB.
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  • Troubleshooting Trailer Wiring Where Turn Signal Isn't Working and Ground is Hot
    The ground wire being really hot is not a great sign. That indicates that something is most likely shorting out to that ground and that would also explain why the one circuit isn't working properly. Trace the hot ground wire and see if you can find where a circuit may be shorting out to it and fix as needed.
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  • Availability of Replacement Tail Light for Cargo Carrier Light Kit
    Yes it is. Part # ST45RB is the Sealed, 4 inch Round Trailer Stop, Turn and Tail Light, Flush Mount, 3-Function and will replace your existing light.
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  • Is Peterson Red Round Replacement Lens # 420-15 Interchangeable with DZ 77-845 Tail Light
    The Peterson Red Round Replacement Lens, # 420-15, is not interchangeable with the DZ 77-845 light that you referenced but I may have a solution. For just a bit more than the cost of a lens, you could replace the entire light assembly with the Sealed, 4" Round Trailer Stop, Turn and Tail Light, # ST45RB. 3-Wire Pigtail, # A45PB, and Rubber Grommet, # A45GB, would be needed in addition to the light. Unfortunately we do not offer a replacement lens that will work for your current light.
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  • Availability of a Round 4 inch Diameter Flush Mounted Clearance Light
    The part # ST45RB is a flush mounted red trailer light that is 4 inches in diameter. The part # STL42RB is also an option. It is LED 4 inch in diameter and has a flange mounted around the outside of it. For more similar options check out the link I attached that has all of the recess mounted 4 inch diameter clearance lights we offer.
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  • Wiring and Mount for Optronics 4 Inch Round Trailer Light # ST45RB
    Sealed, 4" Round Trailer Stop, Turn and Tail Light, Flush Mount, 3-Function Item # ST45RB has a plug in the back to accept pigtail # A45PB. On it the white wire is ground, black is for tail lights, and red is for brake lights and turn signals. This light can be mounted using grommet # A45GB with bracket # BK45BB. Or if mounting directly in a surface you would just need the grommet. I have linked videos of all of these parts for you.
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  • Harness Availability for the Sealed, 4
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  • 4 Inch Round White Trailer Backup Lights Needed for a Quick Loader Trailer
    Yes, we have the Sealed, 4 inch Round Trailer Back Up Light, # BU45CB, that has a clear lens and provides a white backup light. Along with the light you might also need a 4 inch round grommet, # A45GB, and a straight pigtail, # A45PB, or a right angle pigtail, # A47PB.
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  • Troubleshooting Light Not Working with the Cargo Carrier Light Kit # 52014
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  • Will Optronics Submersible Trailer Light ST6RB Work on Malone Kayak Trailer
    The Submersible Trailer Stop, Turn, and Tail Light # ST6RB that you referenced is a great choice to replace the existing lights on your Malone Kayak Trailer. The light housing is designed to allow water to flow in and back out of the housing while being submerged. This light has 6 functions: stop, turn, tail, rear reflex, side marker, and side reflex, and will mount on studs with 2 inch centers. For the left-hand version of this light you will want # ST7RB. For a similarly sized light...
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  • Availability of 2 Inch Diameter 3-Function Taillight
    There is not a 3 function lamp available that has a 2 inch diameter. DOT regulations require that tail lamps meet certain size and visibility requirements. Clearance/marker lights can be smaller, but a 2 inch diameter taillight would not meet those requirements. There is a 4 inch diameter lamp, part # ST45RB. The lamp would typically mount in a grommet like part # A45GB set into an existing hole or using a bracket like # BK45BB.
    view full answer...
  • Replacement Tail Light Recommendation for a 2006 Damon Trailer
    All I really can say is that based on the measurements a previous customer of ours submitted about the tail lights that are on their 2006 Damon trailer the closest replacement we can offer is the Miro-Flex LED Trailer Stop/Turn/Tail Light # STL23R24B. It measures 4 inches in diameter and 1-15/16 inches deep. To install this light, you would also need Rubber Grommet for 4 inch Round Trailer Tail Lights, # A45GB, and Straight 3-Wire Pigtail for Sealed Trailer Stop, Turn and Tail Lights,...
    view full answer...


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