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Old 09-25-2015, 06:37 PM   #31
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I am pulling a 14.5K 5th wheel trailer with my 2013 Ram 3500 dually. During the process of setting the trailer electric brake controller, I had to put 10% gain before I had the ability to slow the unit down from 20 mph with the manual slider on the controller. I had the controller set at Heavy Electric.

I conducted a test, which I am not sure if it was the correct way to check the output from the controller.

With the trailer cable hooked up to the 7 pin connection in the bed, truck running, I took a voltage reading at the brake pin located at the 7 pin connector on the bumper and got the following:

Controller set at 5% gain- 50% brake-1.9 vdc, 100% brake-6.38 vdc.
At 10% gain- 50% brake-6.3 vdc, 100% brake-7.46 vdc.

In addition to the above voltage checks, I also checked amps at each wheel magnet with the following results:

Controller set at 10% gain- amperage at each wheel was- 1.75, 1.78, 1.77, 1.76. Dexter manual specifies 3 amps

Is this the correct way to check controller output? If so, are the output voltages in the ballpark? Does the speed of the truck affect output from the controller when braking is applied? Any assistance would be appreciated.
With a standard multimeter you likely won't see full 12.5v because of the pulse width modulation.

The 2015 ITBM used an accelerometer to adjust Pulse width modulation. I believe there will be a stronger signal when the accelerometer detects preset situations.

When I tested mine with the trailer hooked up I left the key on, set the gain to 10, taped the slider full on and used my MM to get 7.38v. I then unplugged the trailer with everything else set. I popped out the 7pin, unplugged the connector and tweaked the female connector for the brake lead and put it back together. When I retested without the trailer hooked up I measured 10.5v.

I got to thinking yesterday about pulse width and wondered if I needed the trailer load to trigger the PWM. So I hooked up again and measured. Sure enough, 7.84v. While this little bit might not seem like much, that half volt measured by my MM made a huge difference.

Before, my hemi just over powered the brakes and pulled the trailer with its tires turning.

Now I couldn't move it. The harder I pulled, the more the trailer squatted and groaned.

IMO, at 20mph and 10 gain, sliding the slider over should have locked up your wheels. It would have on my father's 2012 Ram 3500. But this is my opinion. The new ITBM might be programmed in a much different way.

In your case, if you feel the brakes are working satisfactory, I wouldn't worry too much.
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Old 09-25-2015, 06:55 PM   #32
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I feel I must state that I am in no way stating all 2015 Rams are affected. If you don't feel your brakes are working as well as they should, this connector is a quick and easy place to look for a potential problem.
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Old 09-25-2015, 07:10 PM   #33
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From the 2015 manual

8.In a traffic-free environment, tow the trailer on a dry, level surface at a speed of 20–25mph(30–40km/h) and squeeze the manual brake control lever completely. 9.If the trailer wheels lock up(indicated by squealing tires), reduce the GAIN setting; if the trailer wheels turn freely, increase the GAIN setting. Repeat steps 8 and 9 until the GAIN setting is at a point just below trailer wheel lockup. If towing a heavier trailer, trailer wheel lock up may not be attainable even with the maximum GAIN setting of 10.
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Old 09-25-2015, 07:24 PM   #34
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My bad I did read it wrong.
If they are using PWM then the duty cycle makes sense if you have an oscilloscope to measure the signal.
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Old 09-25-2015, 07:27 PM   #35
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Mine on my 2015 2500HD work fine. Locks em up at 3.6 at low speeds.

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Old 09-25-2015, 08:06 PM   #36
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My bad I did read it wrong.
If they are using PWM then the duty cycle makes sense if you have an oscilloscope to measure the signal.
He use a scope. He posted pics on the ram page and cummins page comparing his 2013 to his 2015.
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Old 09-25-2015, 08:16 PM   #37
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Mine on my 2015 2500HD work fine. Locks em up at 3.6 at low speeds.

Mel
At 6.5 mine would bring me to an easy stop. No lock up.
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Old 09-26-2015, 12:00 PM   #38
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So here is the latest update. The member who built the test rig has his truck in the body shop at the moment.

HE STILL BELIEVES THE MAIN ISSUE IS CALIBRATION OF THE ITBM. The connector could help many of us. He believes that trailer brake size plays a large factor into why some are not experiencing issues. He has a flatbed trailer with 5" brakes that he has no issues with. 7v is obviously enough to fully engage them. Not so with his 15k Montana 5er.

Here is a scope shot of his 2013 Ram plugged into the Montana. He is getting 12v and duty cycle of 96%.


Now here is his 2015 Ram with the same trailer and settings. 12v max, but look at the duty cycle. 63%, giving him a measured voltage of about 7 vs the 12 on 2013.


And here is a graph and data table to show his test data, even a couple tests of a 2007 Chevy and Prodigy P2 controller. If I am not mistaken, the P2 also has an accelerometer...
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Old 09-26-2015, 12:41 PM   #39
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At 6.5 mine would bring me to an easy stop. No lock up.
I say locking up at low speeds..... when backing up I feel it catch hard.
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Old 09-26-2015, 01:32 PM   #40
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Quote:
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So here is the latest update. The member who built the test rig has his truck in the body shop at the moment.

HE STILL BELIEVES THE MAIN ISSUE IS CALIBRATION OF THE ITBM. The connector could help many of us. He believes that trailer brake size plays a large factor into why some are not experiencing issues. He has a flatbed trailer with 5" brakes that he has no issues with. 7v is obviously enough to fully engage them. Not so with his 15k Montana 5er.

Here is a scope shot of his 2013 Ram plugged into the Montana. He is getting 12v and duty cycle of 96%.


Now here is his 2015 Ram with the same trailer and settings. 12v max, but look at the duty cycle. 63%, giving him a measured voltage of about 7 vs the 12 on 2013.


And here is a graph and data table to show his test data, even a couple tests of a 2007 Chevy and Prodigy P2 controller. If I am not mistaken, the P2 also has an accelerometer...
Here is something stupid. Does the duty cycle increase with speed as opposed to standing still???
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