Why Does My Roadmaster Even Brake # RM-9400 Go to Full Brake as Soon as It Powers On?

Updated 05/20/2026 | Published 05/16/2026

Question:

Hi. I bought a new Even Brake back in January of 2026. It was working fine, no issues. Now, when I install it and apply the 12V power, it immediately goes to full brake, and it takes the compressor forever to shut off. Previous to this, I would install it, power it up, the compressor would run briefly, followed but the red and green test light. I would test and be good to go. So now I cant tow the truck, we are full time. Any help would be appreciated....I did check the owners manual and didnt see anything that resembles this.

asked by: Larry T

Expert Reply:

Hello Larry,

It definitely sounds like something has changed internally with the Even Brake # RM-9400, especially since it was working normally before and now immediately applies full braking pressure as soon as you connect power. Under normal operation, like you described, the compressor should only run briefly during startup while the unit pressurizes and performs its self-test. It should not immediately push the brake pedal to full application or continue running the compressor for an extended time.

The first thing I would check is the position of the actuator arm and the sensitivity settings to make sure nothing was bumped during travel or setup. If the unit thinks the brake pedal is already partially applied when it powers on, it can cause the compressor to keep running and the system to overreact. Try removing the unit completely from the truck and powering it up while it is sitting on a flat surface outside the vehicle. Watch to see if the actuator still extends fully during startup. If it does the same thing while disconnected from the brake pedal, that points more toward an internal issue with either the pressure system or the internal sensor calibration.

Another thing worth checking is the breakaway switch and wiring. If the breakaway pin or wiring has become damaged, shorted, or partially pulled out, the Even Brake can interpret that as an emergency braking event and apply maximum braking immediately. I would inspect the breakaway cable and connector closely for any bent pins, corrosion, pinched wires, or loose connections.

Since the compressor is also taking much longer than normal to shut off, there is a good chance the unit may have developed an internal air leak or pressure sensor problem. That would explain both symptoms together.

If you try those checks and the issue is still happening, please let me know and I would be happy to reach out to Roadmaster directly for you to help get this resolved as quickly as possible. Hopefully we can get you back on the road without too much delay. Where are you all traveling through right now with the truck and RV setup?

expert reply by: Kate F

Roadmaster Even Brake Portable Flat Tow Brake System Installed
(click to enlarge)

Larry T.

5/17/2026

Hi Kate, My first thought was the emergency breakaway wire/pins. I replaced them, they are new. I have not changed anything on the actuator arm, an when installed prior to power, the green light on the relay is off. Something internally has to be wrong. As soon as power is applied it goes straight to full break....never once does it release any air. If you can get some help from RM I would appreciate it. We have to move today, so my wife will just drive the truck. We just left the Sierra Nevada mountains on the way here to Lassen Volcanic NP. Today we are leaving and headed to the Redwoods in Northwestern CA. Then to Oregon, Washington and Vancouver. Everything we have is Roadmaster for towing, heck I even did a nice review of the system to while ago, but we are dead in the water with towing right now. Thanks, Larry

Kate F.

5/20/2026

@LarryT I am really glad you wrote in again Larry, I am not sure why this comment did not show up in my inbox, I am having IT look into it. I appreciate you checking all of that and the extra detail definitely helps. Since you already replaced the breakaway wiring and the unit is immediately going to full brake application without ever releasing air, I agree with you that it sounds like something internal has failed in the unit itself, possibly the pressure control or internal sensor system. I am very sorry you are dealing with this in the middle of a full-time trip, especially with such an incredible route planned. The Sierra Nevadas, Redwoods, and then heading up through Oregon, Washington, and Vancouver sounds like an amazing journey, although I know that does not help much when your tow setup suddenly quits cooperating. I am going to reach out to Roadmaster directly with the details you provided as soon as they get into the office this morning, and I should hear back from them sometime today. Once I do, I will follow up with you as quickly as I can with their recommendations and next steps. In the meantime, I think you are making the right call having your wife drive the truck separately today rather than risking towing without a functioning supplemental brake system. Also, thank you for supporting Roadmaster and for even leaving a review previously. I know they appreciate loyal customers like you, and hopefully we can get this turned around quickly so you can get back to enjoying the trip instead of troubleshooting equipment.

Kate F.

5/20/2026

@LarryT Hey Larry, I heard back from Roadmaster, Tim said it would be best you to call their tech line: 800-669-9690 Please let me know how it goes, and if you need anything else at all from my end, just say the word.

Larry

5/20/2026

@KateF Ok I will give them a call later on this morning. Thanks Kate.