My Surge Brakes Are Activating When I Back Up My Trailer - What Can I Do?

Question:

Im having trouble backing up my boat trailer because the surge brakes wont release. Other trucks can hook up to it without a problem, but I cant seem to get it to work. Weve already changed the plug in the back of the truck, and my lights and turn signals are working fine, so its not a ground issue. Im really confused and could use some help figuring out whats going on!

asked by: Gregg G

Expert Reply:

Hello Gregg, I think I can help shed some light on what is going on. Basically, there are two ways to stop surge brakes from actuating when backing up the trailer.

The first and most popular way to do this is to use a surge brake actuator with a reverse lockout. For example, the Dexter DX7.5L A-60 Brake Actuator # DX56FR has an electric lockout. The solenoid is wired to the reverse light circuit on the tow vehicle. This way when the vehicle is put in reverse, the actuator will be locked out and the brakes will not activate. Not all actuators have an electric lockout though, some have a manual lockout and some do not have a lockout at all. It sounds like your actuator may not have a lockout feature, which would explain what is going on.

I am not sure exactly what model of actuator you have, but it may be possible to add a Reverse Lockout Solenoid like part # T4748800. This solenoid is not universal though, so please do let me know the model number from your actuator so I can confirm fitment.

The other way to stop the brakes from actuating is to use free backing brake assemblies. For an example, the Hydraulic Brake Assemblies # AKFBBRK-35-D are free backing. Meaning the brake shoes will not engage in reverse. Free backing brakes do not require a lockout feature on the actuator. The # AKFBBRK-35-D brakes are intended for a 3,500 lb rated axle. If you can let me know the weight capacity of your axle, I can make sure you get the right size brakes.

Feel free to post any additional info or any questions in the comments below.

expert reply by: Jesse M

Gregg G.

4/18/2024

This is a brand new trailer for a 22 ft tritoon. The brakes work fine when other people back our boat up, Just not ours. I have a 3/4 ton diesel and I believe it is something on my truck that I’m missing.

Jesse M.

4/18/2024

@GreggG I see. I assume then that this trailer does not have free backing brakes and does have an electric lockout on the actuator. Which means that your truck is not sending proper signal to the actuator when the vehicle is in reverse. I have some clarifying questions for you. What is the year make and model of your truck? What kind of plug is this Triton trailer equipped with? Is it a 7-way? Is the truck equipped with a 7-way round trailer plug? If so, was it installed aftermarket or from the factory? If the truck does have a 7 way, I suggest that you use a tester like part # PK12741 to verify that you are getting proper signal on the back up or reverse light circuit when the vehicle is in reverse. Reverse light should be on the center pin of the 7-way. Perhaps the reverse light circuit on your vehicle is pinned incorrectly, or not attached at all. This will be a good place to start. Feel free to comment below and I am happy to assist you further.

Jeff

6/10/2024

@JesseM I have the same problem. 5 pin from trailer to 7 pin on vehicle (using the adapter of course) works fine for a 2016 Suburban LTZ but the surge brakes lock on a 2022 Kia Telluride. Pretty sure I have the exact Dexter actuator referenced (DX56FR) and the solenoid is connected to the reverse port on the 5 pin as expected (along with two other blue wires, presumably the reverse lights). Kia blames it on the trailer connector and the boat shop blames it on Kia - and I get nowhere. Any thoughts would be appreciated.

Marc S.

4/14/2025

Jeff, A voltmeter will tell you right away if you are getting voltage to the solenoid. You will need one or the other of these connectors: 7 pin on the truck side to a flat 5 pin to the trailer or a 7 pin from the trailer. My boat came with a flat 5 pin, So I have to use an adapter........I quickly swapped that out for a 7 pin on the trailer. Less points of failure.