Troubleshooting Brake Controller with OL Code when Brakes are Applied

Question

Question:

When applying controller signals OL

asked by: Frederick L

0

Expert Reply:

If you check out the attached instructions for the Curt TriFlex Trailer Brake Controller # C24VV you can see that the OL code you are getting means that there is an "Overloaded output circuit, trailer brake system fault".

Whichever controller you have the problem and solution is the same. You have a short on your brake signal circuit from your brake controller to your trailer brakes which is causing too much power draw.

Check both the tow vehicle and trailer connectors and make sure they are clean and free of corrosion and debris. If they look good move on to the actual wiring and grounds for the brake circuit and your brake magnets. Make sure the wiring is undamaged and your grounds are securely connected to a clean, bare-metal surface. When you fix this it will fix your code.

expert reply by: Jon G

0

click to enlarge

Dave P.

4/27/2024

I get OL signal without a trailer hooked up. Any comments?

Jon G.

4/29/2024

@DaveP It means you have a short on that blue output wire from the brake controller and it could exist all the way back to the 7-Way pin on your vehicle. Trace that wire and look at all of the connections and pins for that circuit - be sure to fix anything that looks out of place.

Scott

4/28/2025

@JonG We were towing down a mountain and I was applying manual trailer brake input with this unit, when all of a sudden it said OL and has ever since. Even without the trailer attached. Why would it be working (for over a year) then suddenly do that? What all should I check?

Jon G.

4/28/2025

@Scott You'll want to trace the wire I referenced above.

Answer 1

If your 1997 Ford F-150 came with a 7-Way wiring connector at the back from the factory then all of the wiring and everything needed is already on your truck so the installation will be pretty simple! I recommend using the Tekonsha Prodigy P2 #90885…

view full answer...

Answer 2

Try unplugging the brake controller for 10 seconds or so and then replugging it in. Sometimes brake controllers like the part #C24VV just need to be reset and this is the corret way to do that.

view full answer...

Answer 3

The Curt TriFlex NEXT Trailer Brake Controller #C24VV you are looking at is a proportional controller. This means when you press on the brakes the controller is going to have an inertia sensor which then factors in how quickly the vehicle is stopping…

view full answer...

Answer 4

Hey Jeff, we can definitely help but the pins that go into the breakaway switch are not all universal and unless you know what brand it is the best solution is to just replace the entire switch like with the part #420000 as this approach is universal…

view full answer...

Answer 5

The troubleshooting guide included in the instructions for the Curt Discovery Brake Controller #C84VV that you referenced does not include this particular display issue, a flashing 0.0, among the possible display messages. My technical contact at…

view full answer...

Answer 6

If your 2011 Tundra has the factory tow package, which includes the factory installed 7-way trailer connector on the rear bumper, it will be equipped with the tow package plug under the dash, as shown in the photo I've edited for you. Some models…

view full answer...

Answer 7

To install a Curt Brake Controller, like the Discovery #C84VV, on your 2017 Nissan Pathfinder you will simply need to plug the Custom Wiring Adapter #C51382 under your dash like you mentioned. I am attaching a video where one of our install guys…

view full answer...

Answer 8

When installing a hitch that requires drilling on your 2008 Ford Fusion, like the Curt Trailer Hitch Receiver - Custom Fit #C11329, you will need to use a little extra force to pull the bolts through the hole that you drilled. When I first started…

view full answer...

Answer 9

The blue wire of a 7-way runs to the blue wire of a brake controller to activate the trailer's brakes. If you don't have a brake controller or a need for trailer brakes you'd simply not use that circuit. I attached a diagram that has the…

view full answer...

Answer 10

You're right, the mounting bracket is unique (in a good way) for the Curt TriFlex NEXT Trailer Brake Controller #C24VV. The bracket is smaller and all you do is put the included adhesive tape on the bracket and stick it wherever you like under…

view full answer...

Answer 11

It sounds like the red wire in the wiring harness #C51352 was not in the correct place. Take a look at the picture I have included and make sure that the wires in your harness are in the same places. This is the end that plugs into the truck. It…

view full answer...

Answer 12

view full answer...

Troubleshooting Brake Controller with OL Code when Brakes are Applied

Product Page this Question was Asked From

Featured Help Information

Instructions

Continue Researching