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Light Guide LED Backup Light - Submersible - 12 Diodes - Round - Clear Lens

Light Guide LED Backup Light - Submersible - 12 Diodes - Round - Clear Lens

Item # BUL603CB
Our Price: $21.10
You Save: 33%
Trailer Lights
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Shipping Weight: 0.34 lbs
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4" Round. Waterproof trailer light is certified for backup light function in a 2-lamp system when pair of lights is installed. Smooth X-shape crosses the face of the light. Recessed mount with grommet (sold separately). Accepts 2-prong plug. Great Prices for the best trailer lights from Optronics. Light Guide LED Backup Light - Submersible - 12 Diodes - Round - Clear Lens part number BUL603CB can be ordered online at or call 1-800-940-8924 for expert service.
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Optronics Trailer Lights - BUL603CB

  • Tail Lights
  • Round
  • LED Light
  • White
  • 4-1/2 Inch Diameter
  • Recessed Mount
  • Backup
  • Submersible Lights
  • Optronics

4" Round. Waterproof trailer light is certified for backup light function in a 2-lamp system when pair of lights is installed. Smooth X-shape crosses the face of the light. Recessed mount with grommet (sold separately). Accepts 2-prong plug.


  • Round LED backup light for trailers and utility trucks
    • Certified for backup light function in a 2-lamp system when a pair of lights are installed (second light sold separately)
  • Light Guide Series features a smooth X-shape across the face of the light
  • Sonically sealed, waterproof housing and lens unit is submersible
  • Durable surface-mount technology (SMT) construction of LED circuit board
    • Better withstands shock and vibration
    • Allows for improved heat distribution
  • LEDs make great replacements for incandescent lights
    • Last 50 times longer
    • More efficient - provide brighter light with less power output
    • No bulbs to replace - no brittle filaments
  • Durable polycarbonate lens and housing
  • White LEDs with clear lens
  • Compatible with 12V DC systems
  • Recessed mount with grommet (A45GB - sold separately)
  • Accepts industry standard 2-prong PL-3 plug
  • DOT compliant
    • Meets FMVSS 108 requirements in any 360-degree position


  • Dimensions: 4-5/16" diameter x 1-11/16" deep
  • Number of diodes: 12
  • Power draw 12.8V: 0.216 amps
  • Lifetime warranty on LEDs

Optronics BUL603CB Light Guide LED Backup Light Diagram

Sonically 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 housing and lens are sonically sealed together to create a single unit, which means that water will not get into the light and damage the diodes or circuit board.

PL-2 Wiring Connection

Optronics PL-2 Connection

This light has an industry-standard PL-2 connection as pictured above. The light accepts a 2-prong plug (A45CB or A49PB - sold separately). The plug connects to 2 of the points on the PL-2 connection for power and ground. And the plug covers the unused third point on the connection to seal it against dirt and moisture. You will also need a plastic grommet (A45GB - sold separately) to install your tail light.

Recessed-Mount Light

Recessed mount light

Recessed-mount trailer lights install underneath a housing or a grommet, which is often sold separately. These lights will extend into the mounting surface and require that a hole be cut into your trailer.

BUL603CB Optronics Light Guide LED Backup Light for Truck or Trailer - Submersible - 12 Diodes - Round

California residents: click here

Video of Light Guide LED Backup Light - Submersible - 12 Diodes - Round - Clear Lens

Videos are provided as a guide only. Refer to manufacturer installation instructions and specs for complete information.

Video Transcript for Optronics Trailer Lights - Tail Lights - BUL603CB Review

Speaker 1: Today we're taking a look at the light guide LED backup light from Optronics. This is a round backup light that's designed for trailers and utility trucks. Now this is certified for the backup light function in a two lamp system, when a pair of light are installed. The light guide series features a smooth X shape across the face of the light. This is completely sealed. So it features a sonically sealed waterproof housing and lens unit that is submersible.

It features durable surface mount technology, when it comes to the construction of the LED circuit board, that better withstand shock and vibration, and allows for improved heat distribution. Also, it's a complete LED system, so LEDs are a great replacement for incandescent lights, they last longer, burn brighter and they're more efficient. With LEDs, you don't have to worry about changing bulbs, or worry about brittle filaments.Now this is a polycarbonate lens and housing. Its very strong and durable. It's a recessed mount installation with a mounting grommet.

Also, here on the backside, it does accept a Two Wire Pigtail. Now the pigtail and the mounting grommet are sold separately, and are available at You will notice that back here, at the connection point, it does feature three locations, or a three prong connection, but since this is a backup light only, it just needs to be grounded, and it needs to receive power when the reverse lights are activated. So even though it has three ports, you only need to send two functions. So that's why we say that it only accepts or requires a Two Wire Pigtail instead of a Three Wire.Optronics kind of just puts the same footprint, when it comes to the wiring connections, on most of their lights, so don't let that throw you off.

There are three connection points, but this light only require a Two Wire Pigtail.It is SAE and Department Transportation compliant. A few measurements to go over with you real quick, then we'll hook it up to power, so you can see what it looks like with power running to it. Overall diameter, edge to edge, is 4 and 5/16ths inches. And then from the back of that plug housing to the front of the lens, that gives us a measurement of about 1 and 11/16ths of an inch.So you can see here that I only have Two Wires connected, so my white wire is my ground wire. My red wire is for the reverse feed.

And then I do not have anything connected on the black wire. So I am using a three prong plug, but again, I'm only using two functions of it. So it fits in back here. I'll press it in, turn on my power source, turn off my overhead lights, and then I'll activate the reverse gear, and you can see there, it's a nice bright white light. Clear lens allows plenty of light to come through. We're looking at multiple LED's on this unit, so the multi-dio design really helps optimize the overall light output.LEDs have a very, very fast response time as well, so as soon as you engage that reverse gear those LED lights comes on. And when it comes to the power draw at 12.8 volts, we're looking at 0.216 amps, and Optronics puts a lifetime warranty on the LEDs. That's going to do for today's look at the light guide, LED backup light.

Customer Reviews

Light Guide LED Backup Light - Submersible - 12 Diodes - Round - Clear Lens - BUL603CB

Average Customer Rating:  5.0 out of 5 stars   (3 Customer Reviews)

4" Round. Waterproof trailer light is certified for backup light function in a 2-lamp system when pair of lights is installed. Smooth X-shape crosses the face of the light. Recessed mount with grommet (sold separately). Accepts 2-prong plug.





See what our Experts say about this Optronics Trailer Lights

  • Brightest Round LED Backup Trailer Light
    The Light Guide LED Backup Light # BUL603CB you referenced is certainly a nice, bright LED backup light, but the brightest is the GloLight LED Backup Light for Truck or Trailer # BUL101CB, as you can see by the accompanying photo. This light requires Grommet # A45GB and Right Angle 2-Wire Pigtail # A49PB. This does come packaged together with the GloLight LED Backup Light w/ Grommet and Pigtail # BUL101CKB. I have added links to video reviews for you as well which I highly recommend...
    view full answer...
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  • Availability of White LED Backup Light for 24V System
    I do have a solution, but unfortunately the # BUL603CB cannot be used with your 24V system. We have two options available that are specifically made for 24V. Those are the LED Backup Light for Trucks or Trailers - Submersible - 27 Diodes - Round - Clear Lens - 24V # BUL23C24B and the LED Backup Light - 10 Diode - Sealed - 4" Round-White w/Clear Lens-Weathertight Plug - 24 Volts # BUL11CM24B. Both of these lights have a 4-5/16" diameter with a recessed mount. If you need a rubber grommet...
    view full answer...

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Info for this part was:

Employee Cole B
Installed by:
Cole B
Employee Wilson B
Updated by:
Wilson B
Employee Daron K
Edited by:
Daron K
Employee Brian T
Written by:
Brian T

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