Testing Electric Brakes on Trailer without Connecting to Tow Vehicle

Question

Question:

Hello: I want to test the function of my electric brakes...without plugging it into my vehicle. Can I just apply 12vdc and gnd to the brake input wire leads and be able to hear it activate?

asked by: Jeff C

1

Helpful Expert Reply:

Absolutely! If you would rather not connect the trailer to your tow vehicle, you can simply use a separate car/truck 12V battery to test the electric brakes on your trailer. You can apply power to the appropriate brake input pin on the trailer connector (or the wires directly at some point behind the connector) and that will send power to the brakes.

expert reply by: Chris R

1

John B.

7/29/2020

...and that means the brakes will engage? I'm moving a trailer by hand on a flat spot at the top of a hill. It'd be nice to be able to engage the brakes, just in case!

Reply

Jon G.

8/6/2020

Yes, applying 12V power to the trailer brake circuit will engage the trailer brakes. I don't know how easy that will be since you'll be moving it by hand but if you can find a safe way to do this then go for it.

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Bill

6/3/2024

Hi, I bought the 47 pin conversion kit for trailer brakes and ran the extra powerline from the battery to the fuse back to the plug and I wanna make sure that my trailer breaks are correct and proper to use, but I don’t have the trailer yet is there a way I could check that and also is it already set up for a seven pin connection to a RV trailer or is it set up for utility trailer? Thank you.

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Chris R.

6/4/2024

@Bill Hey Bill! You could use a circuit tester on the brake output pin while holding down the manual override on the brake controller - as long as you get 12V power at that pin while doing it, you should be good to go. Don't forget you do still need an actual brake controller in the vehicle's cab. As for a utility trailer or RV/camper, it shouldn't matter as long as you're mating a 7-Way with a 7-Way.

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Answer 1

You can indeed test a trailer's electric drum brakes by directly applying +12V power from a fully-charged battery. You can apply this power to the hot contact on the trailer's plug (see photo please) or to an individual brake assembly's…

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Answer 2

The Replacement Control Panel #LC421484 is the current replacement for your Lippert hydraulic leveling system on your 2014 Keystone Fuzion 399.

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Answer 3

There are a number of reasons why the brakes on your trailer may not be working. Lets start with the easiest things to check. First, check the vehicle and trailer connectors for corrosion. This can cause a short inside the connector and the brake…

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Answer 4

All the brake controller needs to sense a trailer connection so that you can test it is a slight amperage draw on the output circuit. For that you can use a circuit tester like the part #PTW2993 with one pin grounded and the other on the output pin.…

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Answer 5

Something is obviously causing a voltage drop between the brake controller and the trailer connector. The usual culprit in this type of situation is a break in the wire or a corroded wire. Check the wiring under the truck. You should be able to trace…

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Answer 6

Have you tested the brake controller output on the 2025 Silverado's 7-way and confirmed that it's sending power back to the trailer when the manual override is being activated? When you say the brakes aren't activating as they should do…

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Answer 7

Yes, you will want to use a single function diode, like part #RM-690. You will need to wire it in between the breakaway battery and the trailer battery to stop the backfeeding from the battery to the breakaway system.

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Answer 8

If all you want is to prevent the 12 volt power supply of your trailer battery wiring from backfeeding onto your vehicle wiring or vice versa what you need is a one-way diode like part #RM-690. This only allows current to flow in one direction so…

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Answer 9

Yes, there is a measurement you can take to determine what size brakes you need and if they will fit your existing drums. You will want to measure the diameter of your drums. I have included a diagram detailing the dimensions you will need to find.…

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Answer 10

A great way to test the brake controller blue wire output is to use a Circuit Tester, like part #PTW2992. You will want to test the blue wire at the back of the brake controller. If that is low, then there may be an issue with the vehicle wiring. The…

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Answer 11

I'm not sure I totally believe that the problem is a lack of voltage. It's possible this is the case, but12 volts should easily power a camera designed for a standard 12 volt system. I would recommend taking the camera up near the vehicle…

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Answer 12

The voltage at your 5 o'clock plug on your 7-Way trailer connector like #HM40975 should be between the 0.9 you are getting and 12 volts. Test this plug with an incandescent circuit tester like #PTW2993 because it will have a draw on the wire that…

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Testing Electric Brakes on Trailer without Connecting to Tow Vehicle

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