Installing A 3rd LED Brake Light In A 2-Wire System Designed For Incandescent Bulbs

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Question:

I have a 2010 Silverado 2500 HD towing a 30 ft. travel trailer. Trailer has four round trucklite type lights in rubber grommets. These were replaced with very nice LED units. Two on the left operate as tail/turn/brake lights as does the right side. Now I added a LED third brake light bar up higher for some additional safety. When I was doing this I could only find a off brand converter and didnt know about the LED being an issue with these converters. I ended up with a system that works normal until you turn the tail lights on. Thats when the third brake light starts flashing with the directional in use while dimly lighting four of the many Leds in the opposite tail light. The more I looked into it I saw these little notes on sites about not working with the LEDs, and now the use of diodes to prevent back feeds. If I have to replace the converter with a better unit, so be it. Im a little unsure where to put a diode/s in my system. The wiring diagrams on your site seemed to have separate amber turn signals on the trailer where I have two working together. Can you share any advice based on me putting a #118158 in the system ? If this question looks familiar, I sent it to you 4-5 days ago but gave you the e-mail wrong. Thanks

asked by: Kevin S

1

Helpful Expert Reply:

When you turn on the running lights there is more of an amperage draw so that is why the system changes at that point. For your 3rd brake light, I recommend first disconnecting it from your current wiring. Then I recommend using the Vehicle to Vehicle Tail Light Converter # 118158 to splice into your combined right/stop and left/stop wiring. Then connect your 3rd Led brake light to the stop output on the converter. If there is hyper flashing on that third brake light at that point, then install the Putco LED Light Bulb Load-Resistor Kit - Aluminum # DI34ZR between that converter and the light. This creates a stronger draw like incandescent lights need to make your LED lights compatible. You may choose to install these load resisters in line of your other LED lights as well if they have issue. I recommend this over the diode option you mentioned.

expert reply by: Jason S

1

Answer 1

Hey Chris! I can definitely help you get set up to flat tow your 2025 Ford Ranger. Blue Ox is great for the base plate kit and tow bar but I typically stick with Roadmaster for the wiring since they're the most reliable. I recommend the…

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Answer 2

If you aren't getting any trailer lights at all I first recommend testing the connector itself on your F-350 with a circuit tester like #PTW2993. Test the pins while you have a buddy run through the lighting functions in the cab. If you don't…

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Answer 3

It sounds like your trailer tail lights you are using now ground through the mounting hardware. That would be why there are only 2 wires. One of those two wires is going to be for turn signal/brake lights and the other is going to be for running…

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Answer 4

To add a third brake light to your trailer I recommend Optronics Sealed, Streamline LED Trailer Third Brake Light, 1-Function, #STL80RB. This can be wired to your trailer using the Tow Ready Vehicle to Vehicle Taillight Converter, part #118158. To…

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Answer 5

A trailer light that only has 1 wire means that it grounds through its mounting hardware. The single wire is the power wire. The best surface to ground a light to is steel. If steel is not available in the area the light installs you can attach a…

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Answer 6

In order to determine the torque rating for the lug nuts on your trailer you will need to know check out the chart I attached that shows all of the torque specs for all the trailer lugs available based on stud size, wheel material and wheel size.

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Answer 7

A 4-Way trailer connector has the basic lighting functions only; running lights, left turn signal and brake lights, right turn signal and brake lights, and ground. A 7-Way has these functions and a 12 volt circuit, a circuit for electric trailer…

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Answer 8

Both the Roadmaster and Blue Ox tow bars are great options. But if it was my decision to make I would go with the Blue Ox Avail part #BX7420 as we have found that the Blue Ox tow bars are a little easier to connect and disconnect from. Also this tow…

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Answer 9

Yes, it will work. You'll just need to cut the Lance 6-pin connector out and rewire it into the etrailer Trailer Wiring 7-Way Upgrade Kit w/ Junction Box and RV Style Connector item #e99011. Here are the individual functions of that Lance 6-pin:…

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Answer 10

Since wire color codes are NOT universal, we always recommend wiring by function, rather than wire color. If you look at the Trailer Wiring FAQ article I have linked you to, you can see some diagrams showing the proper way to wire a vehicle and…

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Answer 11

The 5.30-12 tires, being wider, are going to make more contact with the road. This means that the noise, and heat build up will be higher than a 4.80-12 tire but the rolling resistance will actually be less because the tire is larger diameter. The…

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Answer 12

The #84 spindle is just a common way to identify the spindle dimensions typically used for 3,500 lb axles. So instead of listing out the parts, people can just say they have #84 spindles and it's easier to know what fits it. The CE Smith Trailer…

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Installing A 3rd LED Brake Light In A 2-Wire System Designed For Incandescent Bulbs

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