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Peterson Trailer Tail Light Kit - Waterproof - Stop, Turn, Tail - Incandescent - Oval - Red Lens

Peterson Trailer Tail Light Kit - Waterproof - Stop, Turn, Tail - Incandescent - Oval - Red Lens

Item # 421KRUS
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Shipping Weight: 0.58 lbs
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421KRUS - Submersible Lights Peterson Trailer Lights
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6-1/2" x 2-1/4" Oval. Waterproof, incandescent trailer tail light functions as a stop, turn, and tail light. Durable polycarbonate lens is welded to housing. Flush mount with included grommet and industry-standard 3-prong plug. (1) Bulb. Lowest Prices for the best trailer lights from Peterson. Peterson Trailer Tail Light Kit - Waterproof - Stop, Turn, Tail - Incandescent - Oval - Red Lens part number 421KRUS can be ordered online at or call 800-298-1624 for expert service.
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  • Reviews (37)
  • Q & A (0)
  • Photos
  • Why etrailer?

Peterson Trailer Lights - 421KRUS

  • Tail Lights
  • Oval
  • Incandescent Light
  • Red
  • 6-1/2L x 2W Inch
  • Recessed Mount
  • Stop/Turn/Tail
  • Submersible Lights
  • Peterson

6-1/2" x 2-1/4" Oval. Waterproof, incandescent trailer tail light functions as a stop, turn, and tail light. Durable polycarbonate lens is welded to housing. Flush mount with included grommet and industry-standard 3-prong plug. (1) Bulb.


  • Trailer light provides 3 functions:
    • Stop, turn, and tail light
  • Sealed, waterproof housing and lens unit
  • Red lens over incandescent bulb
  • Compatible with 12V DC systems
  • Flush mount with included grommet
    • Mounts in any 360-degree position
  • Industry-standard 3-prong plug connects light to trailer
  • Made in the USA


  • Dimensions: 6-1/2" long x 2-1/4" tall x 2-3/8" thick
  • Bulb type: dual-filament
  • Power draw at 12V:
    • Stop/turn: 2.1 amps
    • Tail: 0.59 amps
  • Limited 1-year warranty

Peterson 421 Trailer Tail Light Dimensions

Sealed, Waterproof Trailer Light

The waterproof construction of this light makes it ideal for use on trailers that may be submerged, like a boat trailer. The circuit board is sealed, which means that water will not damage the diodes or circuit board.

Recessed-Mount Light

Recessed Grommet Mount Trailer Light Installation Diagram

Recessed-mount trailer lights install with a grommet, which is often sold separately. These lights extend past the trailer surface and require a hole for installation. If replacing a light, you can utilize the pre-existing hole. If installing a new light, you will need to cut a hole or use a mounting bracket (sold separately) to complete the installation.

421KR Peterson Trailer Tail Light w/ Grommet and Plug - Waterproof - Stop, Turn, Tail - Incandescent - Oval - Red Lens

Replaces 436800

California residents: click here

Customer Reviews

Peterson Trailer Tail Light Kit - Waterproof - Stop, Turn, Tail - Incandescent - Oval - Red Lens - 421KRUS

Average Customer Rating:  4.7 out of 5 stars   (37 Customer Reviews)

6-1/2" x 2-1/4" Oval. Waterproof, incandescent trailer tail light functions as a stop, turn, and tail light. Durable polycarbonate lens is welded to housing. Flush mount with included grommet and industry-standard 3-prong plug. (1) Bulb.

- 421KRUS

Needed on tail light for a friends trailer. I've ordered lights from etrailer in the past and really like the products and ease of installation.

- 421KRUS

Great company to make a purchase from. Products are completely described, communication is great, and delivery is super fast. If you don't purchase trailer parts from etrailer, it's your loss!

- 421KRUS

Delivered quickly. Amazing that a direct replacement was available for a 30 year old trailer.

- 421KRUS

Easy customer service and online orderi ng

- 421KRUS

Great quality and will be perfect for my EZGO

- 421KRUS

Great co. Shipped right on time. Will use for all my trailer needs.

- 421KRUS

Package arrived in great condition, parts were exactly what I was looking for. Thank you!

- 421KRUS

An exact replacement for a taillight on my trailer that was at least 20 years old. Thanks so much!

- 421KRUS

Light kit is overall a nice piece and comes with the installation mounting and wiring parts needed. My only complaint is I had one of the lamps burn out after only a few hours use but that could have been a fluke. For best service life I'd recommend upgrading to the LED kit.

- 421KRUS

exactly what I needed, easy to install and has worked perfectly.

- 421KRUS

Great company to do business with, fast shipping

- 421KRUS

The item fit as a replacement for the original on my Tracker Tahoe boat trailer. However, you will need the connecting wiring for the replacement light due to the original plug will not plug into because of the connecting configuration.

- 421KRUS

These exact Peterson lights were installed on a B&W truck bed 21 years ago from factory. Little has changed over time. The gaskets now are a thinner rubber resulting in a sloppy fit in the hole. They should have left well enough alone.

- 421KRUS

Haven’t installed the lights yet, but the ordered was delivered very quickly, and on time with Based on the estimated delivery time. Many Thanks

- 421KRUS

Great fit, Prefer the LED lights Glad I bought them

- 421KRUS

Excellent products, service and shipping

- 421KRUS

Built solid like all your products. Arrived sooner than expected. Very pleased

- 421KRUS

Quick delivery. My boat trailer tail light and wires came exactly as ordered

- 421KRUS

Purchased replacement light for my boat trailer and what I ordered was an exact fit. Great customer service very knowledgeable thanks Sara E. Will do business with again

- 421KRUS

Great price. "plug and play" with the existing light that had burned out, same plug.

- 421KRUS

Exactly what I was looking for - easy ordering, SUPER FAST shipping, and customer service was excellent. Even followed up with me to ensure I got the right parts. Will buy from them again.

- 421KRUS

Fantastic....just as described and great schematics to help know this was the right part to order for my boat.

- 421KRUS

Nice quick delivery! Fit like a glove t oo! Thanks

- 421KRUS

Have not put it on but it is just what I wanted

- 421KRUS

Fit perfectly. East to install

Show More Reviews

Ask the Experts about this Peterson Trailer Lights

  • What Size Oval Taillights Fit in Buyer's Products 337LB383ALDT Taillight Mounting Box
    The Buyer's Product # 337LB383ALDT taillight mounting box uses a standard 6-1/2 inch oval grommet mounted tallight like those included with the Optronics Fleet Trailer Taillight kit, # 337LB383ALDT. The kit includes the lamps, grommets and wiring pigtails. The lamps have 6 LED's each, and are sealed to prevent water intrusion. They are much brighter than incandescent lamps, draw only a fraction of the power and will last 50 times longer. If you'd rather use incandescent lamps, I'd recommend...
    view full answer...
  • Troubleshooting New LED Trailer Tail Lights Not Working
    No, you do not need to add a converter to your 2011 Ford Ranger for the new LED lights on your trailer to work. If you are not getting power I recommend double checking that your trailer connector has power by using a circuit tester like the # 40376 while the turn signals, then brake lights, and lastly the running lights of your vehicle are turned on. If the vehicle connector has power but the trailer lights are still not working the you will need to double check that the lights were...
    view full answer...
  • Troubleshooting Malfunctioning Marker Lights on Trailer
    First, check to see if any of the other marker lights are working. If not, check that the running lights are working at the rear of the trailer, as they're all on the same circuit. If none of the running/marker lights are working, unplug the trailer and check the running light pin on the vehicle's trailer connector while the headlights are switched on, using a circuit tester like part # 40376. If you get power on the running light pin, the problem is in the trailer wiring. If it's just...
    view full answer...
  • How Does Light Assembly of Peterson Trailer Turn Signal Light # 421KRUS Uninstall
    The light assembly of the part # 421KRUS needs to come out first and then you can remove the rubber grommet. The lip on the grommet prevents it from being able to pull out when the assembly is holding that lip firmly to the cut out of the trailer. You'll want to push the light from behind the assembly out if you can access it or you might need to gently use a flat head screwdriver to pry it out.
    view full answer...
  • Amp Load of Peterson Trailer Turn Signal Light # 421KRUS
    The Peterson Trailer Turn Signal Light # 421KRUS is an incandescent light that draws a max of 2.1 amps. I have added a link to a video review of this light for you to take a look at as well.
    view full answer...
  • Troubleshooting Trailer Running Light Circuit of 2012 Nissan Titan Not Being Active
    Under the dash of your 2012 Nissan Titan there is a relay harness that you will need to check. The top blue relay would be the running light circuit. You can easily test to see if it's bad by swapping one of the nearby blue relays into it's slot to see if the problem goes away (it will then move to a different circuit since the relay is bad). For just a single relay replacement you'd want the part # 38666-1. I attached an install video that shows trailer towing relays installed on a similar...
    view full answer...
  • Is The Peterson 421KRUS Offered In Amber?
    I do have another option that will match what you need, but Peterson does not offer an amber light to match the # 421KRUS, unfortunately. With that said, you will want the Optronics # ST70AB. This incandescent light is the exact same size as the Peterson (6-1/2" x 2-1/4"), but it does not include the gasket or wire. For that you will need the # A70GB and # A47PB.
    view full answer...
  • Grommet Dimensions of the Peterson Light # 421KRUS
    The Peterson Light part # 421KRUS that you referenced includes a grommet that measures 7-5/8" L x 3-3/8" W x 1-1/8" D. Check out the review video I attached for more info as well.
    view full answer...
  • Can The Bulb In A Peterson 421KRUS Tail Light Be Replaced
    The Peterson Trailer Tail Light # 421KRUS is a sealed waterproof unit, but the bulb will technically replaceable. However, removing the cover to gain access to the bulb will damage this seal and the light will no longer be waterproof, so I do advise replacing the entire light if the bulb has gone out. If you do choose to just replace the bulb and break the waterproof seal, I spoke to Peterson and the bulb that fits this light will be the 1157 style bulbs, like the Diamond # DI79VR.
    view full answer...

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Info for this part was:

Employee Mike L
Expert Research:
Mike L
Employee Jameson C
Expert Research:
Jameson C
Employee Joshua S
Video by:
Joshua S
Employee Jacob T
Video Edited:
Jacob T
Employee Laura H
Updated by:
Laura H
Employee Wilson B
Updated by:
Wilson B
Employee Brian T
Updated by:
Brian T
Employee Ryan G
Installed by:
Ryan G

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