Brake controller no tow package -
  • 1 Post By locojeep
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post #1 of 6 Old 07-15-2020, 09:50 PM Thread Starter
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Brake controller no tow package

Hi there a long time lurker first time poster.

I have a 2015 jeep grand Cherokee Limited (no sunroof 😞.

I didn’t have the factory tow package, so I added an aftermarket hitch, and had the ECU flashed by the dealership so that I could tow trailers. I now need to tow a trailer with brakes. I ordered the Tekonsha p3 and the harness it seems to have power as the back light is on but nothing else shows on the screen. I understand it should at least show the logo? Any ideas? Could it be a faulty unit?

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post #2 of 6 Old 07-19-2020, 10:55 AM
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Call them and also try a Google search with the issue you are having.
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post #3 of 6 Old 07-20-2020, 08:48 AM Thread Starter
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Haha, I definitely searched high & low and if you ever called the service center, you know how that often goes. They were confused when I told them I needed them to enable my lights.

Now, to close the loop so that anyone else searching gets the answer.

THE BRAKE CONTROLLER HARNESS IS ENABLED. It turned out I got a bad brand new p3. Replacement units work 100% fine.

And if you are curious here is how I troubleshooted to confirm.

1) Use voltameter on 20v DC, connect to jeep harness- black wire and frame for ground. Confirmed power. Tested the the other wires as well (one if for brake lights so you need to step on brake).
2) connected controller and used voltameter to confirm that brake light and return wire had power when pressing on brakes. I expected this to not work (as the unit is not working) but it did return voltage. So my operating assumption was that the controller screen is not working but the controller itself would technically function (possibly)
3) got a second unit, tested it, everything is fine.
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post #4 of 6 Old 07-20-2020, 10:09 AM
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Have you tried putting the trailer on the hitch locked down? I had a similar problem and ran myself ragged looking for a problem that wasn't there.
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post #5 of 6 Old 07-20-2020, 10:12 AM
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Re-post. the trailer itself has to complete the grounding circuit.
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post #6 of 6 Old 07-20-2020, 10:35 AM
My Reality Check Bounced
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Good catch

I just got lost in thought. It was unfamiliar territory;
Current: 2011 Grand Cherokee Overland V8, 2009 Liberty Rocky Mt V6
Previous: 2000 Grand Cherokee Laredo I6, 1979 CJ7 I6 Quadratrac
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