Troubleshooting a Tekonsha P3 Brake Controller that Reads Trailer Not Connected

Question

Question:

Hello, I can not get my new Tekonsha P3 brake controller to recognize the trailer connection. I purchased the controller and the 2005 F150 specific wiring harness. It always says trailer not connected. I have visually inspected almost all of the wiring, truck and trailer. The lights all work correctly to include brake lights but no trailer brakes. I have also tried checking the wires coming out of the back of the P3. Black was 12v, red is brake lights, white is ground, but blue does nothing. I know blue is the trailer brakes but I get no signal or output when pressing the brake pedal or sliding the manual override on the controller it just clicks and flashes red no connection. I have made sure the fuse for the trailer brakes is good but still no signal?? I have no idea what to even check next. Please let me know what you think. Thank you!

asked by: Dustin

0

Expert Reply:

If you sever the blue wire leaving the P3 controller part # 90195 leaving enough room to reconnect it and test the end of the wire leaving the controller with a circuit tester like part # PTW2993 you should see voltage when you slide the manual override lever. If not, then the brake controller is bad.

If you see voltage there instead then the problem is somewhere on the brake output circuit of your vehicle or trailer. Corrosion on the trailer connector typically causes this problem. If cleaning the connector on your trailer and on your tow vehicle does not fix the problem you will need to inspect the condition of the brake output circuit on both your trailer and on your tow vehicle looking for any obvious signs or shorts like cut or exposed wire and fix as necessary.

I attached an FAQ on troubleshooting brake controller installs for you to check out as well.

expert reply by: Jameson C

0

Chris

4/27/2020

I have the break controller Hooke up with the factory harness that you guys offer. Once the controller gets to 6 volts it shows that there is an open ground . I have by passed that with a separate ground and power lead but still get have the same issue when i apply the breaks. The controller is. Less than a year old could that be bad?

Reply

Chris R.

4/29/2020

A bad controller is possible but unlikely. Since you know the controller's ground is good, I would inspect both the vehicle's and trailer's 7-Way connector. Visually inspect both to check for any corrosion or debris that might be built up around/inside the pins, cleaning out as needed. Let me know if this doesn't help and we can go from there.

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Chris T.

4/29/2020

Both. Trailers are new And both plugs on the truck are new. The truck is a 1998.5. Dodge 2500. In one of your install videos. It makes reference. To if the plugs are not a factory. Plug. There might be something else I need to do to make them work but does not say what? The controller. Recognizes the trailers all the lights turn signals and break lights work. But when you ask for a lot of break. It goes to broken ground no breaks. Is there I a difference between. The wire harness that you guys sell For the 1998. And 99.

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Chris R.

4/30/2020

The truck is recognizing the new brake controller so you shouldn't need anything else done (the video was likely talking about taking the truck up to a dealer to have the computer flashed). If I understand correctly I believe you said the same issue is happening on two different trailers? If that's the case then we at least know the problem is somewhere on the truck. Does the problem occur both when pressing on the brake pedal and when using the manual override? If it's just with the brake pedal the brake switch on the truck itself could be going bad, which isn't terribly uncommon on older trucks.

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Answer 1

I am not entirely sure what process you took so I'll give you some other things to try, or maybe a different way to test the Prodigy P3 #90195. First, sever the blue wire a couple inches from the back of your controller. Then use a circuit…

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Answer 2

I would start by inspecting the connector on your trailer and the vehicle to make sure there is not corrosion in the connector which could be causing a bad or weak connection. If there is corrosion in the trailer side connector, you would need to…

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Answer 3

You are correct, you should only be getting output when the brake is applied, or the override switch is activated. It sounds like the controller might be bad, but to make sure, you should probably bench test it before tossing it. Use a circuit…

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Answer 4

If your Tekonsha P3 Brake Controller, part #90195, displays the error message OUTPUT SHORTED NO BRAKES, the potential causes are a short in the brake output circuit somewhere between the brake controller and the trailer brake assemblies, or a shorted…

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Answer 5

It does sound like there is a possible short with the brake magnets on your trailer, especially if all the wiring looks good between the brake controller and vehicle connector. I recommend first making sure that each magnet has one wire secured to…

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Answer 6

The "Warning Output Shorted No Brakes" error message on the Tekonsha Prodigy P3 Trailer Brake Controller part #90195 per the manual can be caused by one of two things. I have listed these for you below: 1. Detects brake output wire shorted…

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Answer 7

I would start by inspecting the connection on both your vehicle and trailer. This issue is often caused by corrosion on the 7-way connections. It probably wouldn't hurt to clean the connections one way or another. If this does not solve the…

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Answer 8

If you are getting a no trailer connected warning on your Tekonsha Prodigy P3 #90195 you may have a corroded or dirty connector which is hampering the connection. Check the vehicle and trailer plug to see if there is any type of corrosion or dirt…

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Answer 9

The wiring harness you should be using on your 2013 Toyota Tundra is #3040-P. While it is unlikely it is wired incorrectly it is possible. You can use your test light to test the connector on the vehicle (where 3040-P plugs into) and see if it has…

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Answer 10

Yakima and Inno bases are not compatible with the Thule roof bars. In general, each manufacturer has its own mounting methodology and kits, so the bars are not usually compatible. Your roof box, however, would be likely to fit onto the available…

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Answer 11

To determine if there are compatible hubs and associated bearings to replace your current hubs to a more standard size you will have to take several precise measurements on the spindle of your axle. It is recommended to use a set of dial calipers to…

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Answer 12

I do have a possible solution for you to add sway control to your straight tongue trailer, but unfortunately adapters like part #RP58393 are not designed to be used with friction sway control units like you would find in the Kit #83660. If you have…

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Troubleshooting a Tekonsha P3 Brake Controller that Reads Trailer Not Connected

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