Installing New Trailer Lights and Wiring on a Horse Trailer
Question:
I am rebuilding my horse trailer and I am replacing all the lights. I am going to the 4inch round flush mount lights mounted in rubber mounts. I need all the clearance lights as well as the associated plugs to hook up the lights. Do you sell complete kits or do I need to piece everything together? I do not need led, they would be nice but I know they cost more. I am also looking to work on a budget.
asked by: Gordon J
Helpful Expert Reply:
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 junction box. Most molded 7-way pigtails will come wired with the RV style color code. If you ever need to replace your 7-way connector in the future, you could simply open the junction box, remove the connector and wire loom and install a new, molded 7-way trailer connector.
I have attached a video showing the installation of the junction box. In this video, our installer uses a 7-way molded connector with the RV style color code like your 7-way connector. He also uses the traditional wire colors going out of the junction box to the trailer lights and brakes. He uses the appropriate lengths of 16 gauge Bonded 4 Wire, # 16-4B-1, for the trailer lights and 10 gauge Jacketed 2 Wire, # 10-2-1, for the trailer brakes and ground.
Additional hardware that you may need is 3/16 Inch Ring Terminals, # 44-5310A, 1/4 Inch Ring Terminals, # DW05702-1, 12-10 Gauge Butt Connectors, # 05732-2, 16-14 Gauge Butt Connectors, # 05731-5.
You didn't mention what clearance lights you are interested in so I attached a link to a page that has all of the ones we carry.

Products Referenced in This Question
16-14 Gauge Butt Connector - 5 Pack
- Wiring
- Wire Connectors
- Butt Connectors
- 16-14 Gauge
- Deka
more information >
Deka Jacketed 2 Wire, 10 Gauge, Brake Wire - per Foot
- Wiring
- Wire
- Jacketed Wire
- 2 Wire
- 10 Gauge
- Deka
more information >
16 Gauge, 4 Conductor Bonded Parallel Wire - Per Foot
- Wiring
- Wire
- Bonded Wire
- 4 Wire
- 16 Gauge
- Deka
more information >
Ring Terminal - 12-10 Gauge Wire - 3/16" Ring ID
- Wiring
- Wire Connectors
- Ring Terminals
- 3/16 Inch Diameter
- 12-10 Gauge
- Flint Hill Goods
more information >
Rubber Grommet for 4" Round Trailer Lights - PVC
- Accessories and Parts
- Trailer Lights
- Mounting Hardware
- 4 Inch Diameter
- Grommet
- Round
- Optronics
more information >
3-Wire Pigtail for Optronics Trailer Lights - 3-Prong PL-3 Plug - 10" Lead
- Accessories and Parts
- Trailer Lights
- Wiring
- Plugs and Pigtails
- 10 Inch Long
- Three Wire
- Straight Pigtail
- Optronics
more information >
Ring Terminal -16-14 Gauge - 1/4" Ring ID - Qty. 1
- Wiring
- Wire Connectors
- Ring Terminals
- 1/4 Inch Diameter
- 16-14 Gauge
- Deka
more information >
Product Page this Question was Asked From
Optronics Trailer Tail Light - Stop, Turn, Tail - Submersible - Incandescent - Round - Red Lens
- Trailer Lights
- Tail Lights
- Stop/Turn/Tail
- Round
- Recessed Mount
- Submersible Lights
- Incandescent Light
- 4-1/4 Inch Diameter
- Red
- Optronics
more information >
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