Rewiring A Trailer That Has Incandescent Lights With LED Lights
Updated 09/29/2026 | Published 09/28/2026
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Question:
I have a 16 trailer 14 wood deck with 2 steel dovetail that has incandescent lights and had brakes at one point or another I believe. I moved across the country and left it with my parents for a couple of years during which it was used by a friend of the family who opted to go in an fix a couple of lights by cutting the harness and splicing in new sections and just made a giant mess. This brings me to my current situation and reason for this message. See current setup below: Clearance markers - 2 round recessed mount with rubber grommet 4 amber, 7 red Stop/Tail/Turn - 6 1/2 x 2 oval, recessed mount with rubber grommet 2 Tag/License plate light - Unknown, there is the remains of a fixture there but it is gone. State law does not require tagging of trailers. What I would like to do is to start over from scratch on this thing and install LEDs. I can no longer stomach the idea of rubber grommets. These things will be the end of me one day. I have already added the following to my cart: Red marker - MCL52RB x7 Amber marker - MCL52AB x4 2-wire pigtail - A46PB x11 STT - STL78RB x2 3-wire pigtail - A47PB x2 I went with these simply for the flange that I can use to mount using the existing holes without the grommets. Ideally I would have liked to have found clear lens lights all around, but that isnt a requirement. I would like to be able to add additional lights along the sides but I am not sure how many more I would be able to. I know going from incandescent to LED means a lower draw is produced give more headroom right?. I want to install a junction box for sure and I dont know which wiring I need for this project. Is there any way someone could lend an assist to get me headed in the right direction? Thank you for your time.
asked by: Kody B
Expert Reply:
Hi Kody!
It looks like you are well on your way! A junction box will definitely make the process of getting this done faster and easier, so it is a highly recommended part. I tend to prefer the etrailer Trailer Wiring 7-Way Upgrade Kit w/ Junction Box and RV Style Connector # e99011 since it already has half the wiring done, but really any of them would work. Plus it includes the needed ring terminals.
10 Gauge Wire - Blue Primary - Per Foot # 10-1-1 for brakes and/or other 12v accessories and then the 16 Gauge, 4 Conductor Bonded Parallel Wire - Per Foot # 16-4B-1 is what I would use for everything else. I would also use the Deka Heat Shrink Butt Connector - 16-14 Gauge - Nylon Insulation - Blue - Qty 10 # DW05744-10 and Deka Heat Shrink Butt Connector - 12-10 Gauge - Nylon Insulation - Yellow - Qty 10 # DW05745-10 to make all the connections. Heat shrink will help keep the connections nice and dry, so they are highly recommended when wiring up a trailer. I do want to ask though, why the 3 prong # A47PB? The only light you mentioned that has a 3-wire connection is the # STL78RB, but that has bare wires and not a plug in the back.
And to your question about being able to add more LED lights than you could with incandescent, that will be a yes. LED lights require a lot less power to run, so you will be able to add significantly more. I can't tell you exactly how many more LED lights you can add, but they draw anywhere between 75% to 90% less power than an incandescent light, so that should give you an idea of what you can do.
What are you going to be using the trailer to carry?
Product Page this Question was Asked From
etrailer Trailer Wiring 7-Way Upgrade Kit w/ Junction Box and RV Style Connector
- Trailer Wiring
- Trailer Connectors
- Trailer End Connector
- 7 Blade
- Plug and Lead
- etrailer
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Kody B.
9/28/2026
I didn’t notice the tail lights already have wires. Thank you for pointing that out! This trailer gets used to haul everything from loads of hay bales to the occasional small tractor or car and everything between.