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7" Round Transit Turn Signal Light - Amber

7" Round Transit Turn Signal Light - Amber

Item # ST90AB
Our Price: $14.30
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7-1/8" Diam x 2-3/16" D; Weather-tight seal w/gasket; replaceable lens and bulb; surface mount on 6-1/4" centers; 2-wire; 1-bulb incandescent Great Prices for the best trailer lights from Optronics. 7" Round Transit Turn Signal Light - Amber part number ST90AB can be ordered online at or call 1-800-940-8924 for expert service.
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  • Reviews (15)
  • Q & A (0)
  • Videos (1)
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Optronics Trailer Lights - ST90AB

  • Tail Lights
  • Round
  • Incandescent Light
  • Amber
  • 7-1/8 Inch Diameter
  • Surface Mount
  • Non-Submersible Lights
  • Turn
  • Optronics

7-1/8" Diam x 2-3/16" D; Weather-tight seal w/gasket; replaceable lens and bulb; surface mount on 6-1/4" centers; 2-wire; 1-bulb incandescent

7" Round Transit Turn Signal Light - Amber

This is a round transit light used as a turn signal light. This amber light is 7-1/8" in diameter by 2-3/16" deep. The light includes a gasket for a weathertight seal against the elements. The light features a replaceable, screw-down lens and easy-to-replace bulb. This light surface mounts through holes placed at the four "corners" along the edge of the light. The holes are spaced 6-1/4" across the light. The wiring design contains the lead wires for power and is grounded through the mounting hardware.

  • Amber, round light functions as turn signal light
  • Gasket is included to create weathertight seal
  • Replaceable lens and bulb
  • Wiring design contains lead wires and grounds through mounting hardware
  • Surface mounts with four holes at 6-1/4" apart across center of light
  • Dimensions: 7-1/8" Diam x 2-3/16" D

Manufacturer Specifications

Amber rear turn signal for surface mount. Gasket for water tight seal provided. Features screw on, replaceable lens and easy to change replaceable bulb. Contains both lead and ground wire for mounting to all surfaces.

dimensions of light

ST90AB 7" Round Transit Light - Amber by Optronics, Inc.

Alternate part number: ST-90AB

California residents: click here

Video of 7" Round Transit Turn Signal Light - Amber

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 - ST90AB Review

Today, we're going to review part number ST90AB. This is the Optronics seven inch round transit turn signal light with the amber lens. This is an amber round light, which will function as a turn signal light. This light will surface mount using these holes right here on the outer edge. There is four holes. They are placed at the outer edge.

They are spaced six and a quarter inches across. If you measure directly across center to center, there is your six and a quarter inches. It does include this foam gasket. This helps create a weather tight seal for your light. The lens itself also is a replaceable screw down lens. You can unscrew the four screws, take the lens off, you can even access the bulb if you need to replace the bulb. The wiring design on this light: It takes one hot twelve volt wire.

It will ground through the mounting hardware so when you install your mounting hardware to install this on the vehicle, that is what will ground to the vehicle or the trailer, wherever you're hooking it to. I'm going to give you a few dimensions on this. Again, the diameter edge to edge will be right at seven and one eighth inches. The depth from the front to the back, it's going to be right at two and three sixteenths. Again, I mentioned here is the mounting holes we talked about. If we go center to center, six and a quarter inches. What I'm going to do is plug this in to our twelve volt power supply to give you an idea of how bright this turn signal light is.

What we're going to do is take the power wire, we'll go ahead and hook that to the wire lead coming out. For grounding, what I'm going to do is use one of these screws right here to get a good ground. Actually, when you go to install it, when you put your mounting screws in here to install this, that's where you'll get your ground from. We'll go ahead and hook it up to here. Now, what I'm going to go ahead and do is turn off the overhead lights, go ahead and turn on the twelve volt power, and there is how bright your light would be as a turn signal. Very large, bright light.

I'm going to turn off our power, turn back on our overhead lights. That should do it for the review of part number ST90AB. This is Optronics seven inch round transit turn signal light with the amber lens. .

Customer Satisfaction Score:

Customer Reviews

7" Round Transit Turn Signal Light - Amber - ST90AB

Average Customer Rating:  4.8 out of 5 stars   (15 Customer Reviews)

7-1/8" Diam x 2-3/16" D; Weather-tight seal w/gasket; replaceable lens and bulb; surface mount on 6-1/4" centers; 2-wire; 1-bulb incandescent


The reflectors were delivered promptly, were packaged well, and work wonderfully!Great customer service as well?


Good transaction for some bus lights.


Perfect for my vintage camper. The front previously had lights mounted on the front bottom. These fit the size and holes perfectly. I am going to wire them as running lights only.


Am doing a school bus conversion. Existing lamps were badly rusted[all 4]. Local parts house was no help, went to the WWW and up popped etrailer.
Ordered on Wed, received on Sat. Prompt and fair priced.
Will install them this pm.Very happy.


Close to the original on a 2004 Bluebird school bus, but with a much better, sealing gasket!


Product is holding up fine. Our customer is very satisfied.


I have a 61 Superior GMC flat nose bus and this will work great for the old ones that were on the front where to Sun rotted to use


Had what I needed and delivered fast!


Perfect match for my 1996 school bus.


lights are as we expected
Very well


Arrived in one piece. Wish shipping was faster.


Quick shipping. Great packaging and com munication






See what our Experts say about this Optronics Trailer Lights

  • Recommended 2-Wire To 3-Wire Adapter To Add Additional Turn Signals On 2018 Class C Motorhome
    Absolutely! You will need the Curt 2-To-3-Wire Tail Light Converter # C56196 which will convert the 2-wire system on your 2018 Class C Motorhome built on the Ford E-450 Chassis to a 3 wire system. This will give you the separate turn signal wire you need to install an additional amber turn signal like the 7" Round Transit Turn Signal Light # ST90AB or which ever light size and design you prefer. Keep in mind that none of the 2-to-3 wire converters currently offered will work with LED...
    view full answer...
  • Replacement Lens For 7" Round Amber Light Using 4 Mounting Holes
    The Lens # A90AB you found is our only 7" round amber lens. This is a replacement for the 7" Round Transit Turn Signal Light # ST90AB. We do have an LED # STL90AB version of this light as well but no lens only for the LED version.
    view full answer...
  • Is there a Signal Contact Version of the Optronics Dual Face Trailer Parking/Turn Signal Post Mount
    According to my contacts at Optronics they do not offer a single wire system. The wires on this particular light are as follows: Red wire - parking light Black wire - turn signal Furthermore this light grounds through the mounting bolt to the trailer. I have checked our and we do have the Optronics 7 Inch Round Transit Turn signal # ST900AB that only has one wire. This light serves as a turn signal only and is a single sided light not double sided like the product that you referenced....
    view full answer...
  • Round Amber Lens Light for Trailer
    The Trailer Dome Light w/ Steel Base # IL91CB is designed as an interior light and isn't available with an amber lens, but you might be interested in the Amber 7" Round Transit Turn Signal Light # ST90AB instead. This has a 7-1/8" diameter and has a weathertight seal so it can be used on the outside as well as the inside if that's what you're wanting. These have similar dimensions so the real difference is the light you were looking at has the chrome base and this option does not.
    view full answer...
  • 2001 Chevy Silverado 3500 Tail Lights Not Working and Brake Signal on 7-Way Not Working
    From what I have been able to find, the 2001 Chevy Silverado 3500 had what is called a 3-wire system. This means the turn signals are separate from the brake lights. If the lights you are using are designed for a 2 wire system then it they will not function properly. There are 2 possible options. First, you can get lights that do have separate turn signal functions. Second you can use a special converter on the truck wiring to take the separate signals and combine them to a 2-wire system...
    view full answer...

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Info for this part was:

Employee Laura H
Updated by:
Laura H
Employee Wilson B
Updated by:
Wilson B
Employee Brian T
Updated by:
Brian T

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