Electric Trailer Brakes Wont Release After I Hit Brakes
Published 11/16/2016 >
Products Featured in This Question
Question:
I just bought this trailer 9 ton 3 axles. It had a 5 pin plug I changed it to a four pin left out a blue wire.i thought was the electric brakes. I drive down the road and the electric brakes ingauge when I apply my brake in the truck and wont release. I cut the red power wire off the plug and the brakes released. Is this blue wire to release the brakes? Or do I just need a 7 pin to correct this.
asked by: Joe
Expert Reply:
On a 5-way connection, the blue wire is normally for the brake controller as you stated. However the color of the wire in this case probably won't help us as it is evident this connection has already been tampered with. I have attached a trailer wiring diagram for you. The focus should be on the function of the wire and not on the color of the wire, so we can pair the correct functions at the trailer and vehicle connection points.
To test the trailer wires, you can get a 12 volt batter with two leads connected. On to positive and one to negative on the battery. Connect the negative lead to the trailer ground and then use the positive lead to figure out the light function of each wire. Power to the brakes should activate the brakes and release when removed from power.
I recommend with that big a trailer that you use trailer brakes, and would upgrade to a 7-way connector. I recommend using the Universal Installation Kit for Trailer Brake Controller - 7-Way RV and 4-Way Flat, # ETBC7. This kit will allow you to connect your 4 way flat from your tow vehicle into the connector and then you connect the reverse wire if desired and run the power and brake controller wire. This kit includes everything you need from wire, to connectors, to circuit breakers. I have attached the instructions as well as an installation video for you.
You can use any brake controller with this system, but I recommend the Tekonsha Prodigy P3, # 90195. This controller is an easy to read option with an LCD screen. It gives three different boost options and runs constant diagnostics without the hassle of deciphering codes.
For the trailer, I recommend the 7-Way Molded Trailer Plug with Junction Box # HS381-9000. This will allow you to convert your current trailer brakes into a 7-way connection with easy connection points that make any future issues easy to identify.
Product Page this Question was Asked From
Electric Trailer Brake Assembly - 10" - Right Hand - 3,500 lbs
- Accessories and Parts
- Trailer Brakes
- Electric Drum Brakes
- RH
- 3500 lbs
- Brake Assembly
- Manual Adjust
- 10 x 2-1/4 Inch Drum
- etrailer
more information >
Featured Help Information
Miscellaneous Media
Continue Researching
- Q&A: Replacement Dexter Brake Assemblies for 023-027-00 and 023-026-00
- Q&A: Trailer Hitch and Wiring Recommendation for 2026 Toyota Rav4 Limited
- Q&A: Can etrailer Electric Trailer Jack Work Without Trailer Battery
- Article: Electric Trailer Brakes: How They Work & What to Buy
- Q&A: Looking for Trailer Hitch that Fits 2026 Toyota RAV4
- Article: Trailer Wiring Diagrams
- Q&A: Noise from Newly Installed Electric Brake Magnets and Drums on Travel Trailer
- Q&A: Mounting Plate Dimensions For ARK Xtreme Off-Road Ratcheting Trailer Jack # ARK54FR
- Q&A: Which Brake Assembly Does Part Numbers B10E-21 & B10E-22 Correspond to?
- Article: Trailer Lighting Requirements
- Article: Replacing the Bearing, Races and Seals on a Trailer Hub
- Article: Trailer Drum Brakes vs. Disc Brakes: Making the Decision
- Article: Most Popular Wheel Bearings
- Article: Which Sway Control Hitch is Right For Your Trailer?




