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These smart diodes ensure your RV's brake and turn signals display correctly on your car's multiplex LED tail lights. Prevents damage from electrical feedback. Includes 2 diodes.
Features:
Note: If you need a complete kit with wiring and installation supplies included, pick up RO44FR (sold separately) instead.
A variable voltage tail light (also known as multiplex) uses the same wire for both the brake light and the tail light, sending a 12-volt signal to the brake light and a 9-volt signal to the tail light. This works fine when you're driving, but when you are flat towing, the RV will send a 12-volt signal to both the brake light and tail light, making them the same level of brightness and impossible to distinguish from each other. The drivers behind you won't be able to tell the difference between your tail lights and your brake lights, which is a huge safety issue.
These smart diodes solve that problem by simply converting the signal from the RV to the lower voltage needed for your car's tail lights. They install permanently, but don't worry; everything will work as normal when you're not flat towing.
This kit is designed to work with LED lights only, so if you have incandescent variable voltage lights, you'll need kit RO34FR (sold separately) instead.
Customer Satisfaction Score:
93% were satisfied with this product
7% of customers were not satisfied
Ratings & Reviews
Perfect besides packing is all bent up
Great service, when I called they were very helpful
This product works very well but the wire diagram was not correct.
I had to develop a method to make them work for my 2015 Ford Edge SEL.
Worked as advertised.
The diodes have functioned without fail.
Great service and great job keeping us updated with the transit. We will definitely shop here again! Thank you.
It wasn't what I really wanted wouldn't use this next time, but already bought. There is better and cheaper on the market.
I haven't used them yet.
They work great and are a nice compact size. However, the instructions on the packaging is different than what is shown on the actual device leading to confusion.
Excellant kit with easy instruction to follow. Lights worked great, very happy.
It’s very good thanks
installed fairly easy ,once i got wiring diagram for 2020 jeep gladiator/with LED lights LED tail lights need smart diodes ,not 4 reg diodes
The dealer installed the wrong diodes for our tow set-up and our lights never worked properly. Looked on etrailer and found a how-to video that explained the problem, ordered this product (the correct diodes), and now everything works just as it should.
work great and easy to install.
David
6/4/2025
Still working great
There needs to be more clarity on which ones are needled to work with vehicles. I ordered the kit that has more diodes. After opening the kit and called the help line and was told it will work. So I even emailed asking to order the smart diodes if they could discount them because I already opened the package on fist order and I could still use the rest of wiring. No response so I just ordered the right ones. There is no room for more than one diode.
Unfortunately replacing the stereo did not fix my left tail light issue. I fear it's a possible wiring issue and unfortunately I live in Arizona and there is no e-trailer down here for me to take it to for repair. I would imagine the new diodes are perfectly fine
Very fast shipping of quality products.
Just what i needed to connect my 2020 Sierra 3500 HD up to the motorhome to be towed. My Sierra came with LED taillights, which are not standard for that year.
Its an easy install. It took longer to run the wires from the front bumper to the tail lights.
This review isn't about the product which works great, it's about the employees. I ordered the part and was to be delivered the next day. That didn't happen. Finally got that part(which was the wrong part, my fault not theirs), on Wednesday due to a screw up with UPS. Called on Saturday and talked with Adam who sent the correct part out same day!! Got it today and will install tonight. Still would like to see a credit on my overnight shipping from last week, but that's another issue.
Joe
1/24/2026
It’s still good. If you aren’t close to flat or straight it will bind. Really have to be forceful with it unless the toad is flat and straight behind motorhome. Then it’s a piece of cake.
Kate F.
1/26/2026
I purchased a complete flat tow package from etrailer. When I installed everything I found out that my lights were both incandescent and led so I called etrailer and Jeremy sold me the Smart Diodes for variable Voltage LED Tail Lights. This was the perfect solution to my problem. Just towed over 800 miles without any issues.
Thank you to etrailer for getting me on the right path.
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Robert
4/30/2026
It works! It took a bit of test wiring, to finally get the right wires connected to the right leads on the diodes, but that was due to my inexperience. After a year, the system still works as expected.