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

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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

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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.

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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…

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Answer 4

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…

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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…

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Answer 6

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…

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Answer 7

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…

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Answer 8

On your Curt TriFlex Trailer Brake Controller #C24VV, the decimal point as you put it is standby mode with no trailer connected. The blank screen is also standby mode and that screen is what is seen when simply starting the vehicle, but that screen…

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Answer 9

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…

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Answer 10

Unfortunately the Atwood 85736 cannot be replaced so you'd actually need an entirely new actuator. The closest replacement we have is the Demco Hydraulic Brake Actuator #DM72VR. This actuator has a gross towing weight capacity of 7,000-lbs, a…

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Answer 11

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Answer 12

The 7-Way trailer connector on the back of your 2003 Chevy Silverado should have a round plug behind it that plugs into another harness that continues up to the front of the truck. What you can do is use #C55774 which comes with a new mounting…

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Troubleshooting Brake Controller with OL Code when Brakes are Applied

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