How To Power A Third Brake Light With Diode Wiring While Flat Towing
Updated 04/16/2025 | Published 07/12/2022
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Question:
I recently purchased a RM47ZR wiring kit for a 2021 Jeep Wrangler High Altitude with LED lights. I noticed on the video when they were testing the stop lights on the jeep the third brake light did not illuminate when it was tested. Is there another connection that can be made so the third stop light will function when hooked to the motor home? Thanks
asked by: Bill H
Helpful Expert Reply:
The reason the third brake light isn't coming on is because the Roadmaster Wiring Kit with Smart Diodes for Variable Voltage LED Tail Lights # RM47ZR is only being wired to the just the tail lights. To get the third brake light to activate you would need to splice in a jumper wire between the third brake light and the the "RV Brake In" on the diode.
You would need an additional Smart Diode # RO54FR for the third brake light and essentially wire it the same as one of your tail lights. The jumper wire can be placed on either tail light and just be twisted together with the "RV Brake In" wire before you crimp it into the spade terminal and connect it to the Smart Diode and then ran up to third brake light.
Product Page this Question was Asked From
Roadmaster Smart Diode Kit for Variable Voltage LED Tail Lights
- Flat Tow Wiring Harness
- Splices into Vehicle Wiring
- Diode Kit
- Universal Fit
- Roadmaster
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Rod Z.
4/16/2025
Have installed Roadmaster Smart Diodes on 2022 Jeep Gladiator, which I flat tow with Newmar Ventana. Would like to install brake/turn/running lights on back of truck cap to provide high up lighting because the regular taillights are blocked by the bike rack and bike covers. Can I jumper the rv brake, rv tail and car brake feeds into the existing Smart Diodes into additional smart diode per side and connect to smart diode car brake out and ground? Assuming this is correct, thinking of Part Number DG52435VP, but which wire would I use to connect to the smart diode car brake out, the red brake or black tail light wire ? Thank you, Rod Z