Brake Controller

[drittal]

Amen!



That is the question I'm trying to get answered, my 3500 is at the dealer now, should have it back with answers Monday.

I don't know if it is a faulty ITBM or a software calibration issues. I don't even know if all 2015s have the issue but I know I'm not the only one with this issue.

My biggest concern is they are going to tell me nothing is wrong and it is working as designed, the default babble when they don't know how to diagnose an issue.

I posted scope shots of the trailer brake line (in the cummins forum thread), one with a working ITBM and my 2015 tow vehicle, the scope shots clearly show my 2015 is only outputting 63% power to the trailer brakes.

Brake slider all the way pushed (100%), 100% output from ITBM 12.6 amps measured on the trailer brake wire.


Brake slider all the way pushed (100%), 63% output from ITBM 6.1 amps measured on the trailer brake wire.

Boss,
looking at these scope shots... I downloaded them so I could zoom in. The vertical axis is Volts, correct? Now it seems both trucks are sending 12v, but the pulse width is much different. The 2015 has a longer 0v period. The 2013 has a very short period of 0v in comparison.

Now, looking at the pics CC posted with the operation of the 2015 ITBM it states that it has an accelerometer the will adjust the Pulse Width. This is to reduce trailer brake wear.

Humor me, can the static difference be caused by the accelerometer? Sitting still the accelerometer is not sensing any forces, where the 2013 is just braking a predetermined amount.

 

[cc rider]

Damn! Getting all "tecchy". I like it! Somebody has to figure it out since the clowns at the dealer can't

 

[BossHogg]

From the different forums I have found this on the controller isn't the issue, it is the connector.

A person on the Airsteam forum reported their RV dealer fixed his issue in the connector. What is not known is what voltage his trailer needs to stop hard. If his trailer has, for example, 5 inch brakes, then he will never see the issue of low voltage since smaller brakes require less voltage.

I bought the Prodigy cable that plugs into the RAM ITBM connector and my Prodigy P2 brake controller, installed the P2 in my 2015 RAM 3500. The P2 provides full voltage to my trailer so this rules out a wiring or connector issue, at least on my truck. I know from reading around, others have gone the same route with the same success.

Boss,
looking at these scope shots... I downloaded them so I could zoom in. The vertical axis is Volts, correct? Now it seems both trucks are sending 12v, but the pulse width is much different. The 2015 has a longer 0v period. The 2013 has a very short period of 0v in comparison.

Now, looking at the pics CC posted with the operation of the 2015 ITBM it states that it has an accelerometer the will adjust the Pulse Width. This is to reduce trailer brake wear.

Humor me, can the static difference be caused by the accelerometer? Sitting still the accelerometer is not sensing any forces, where the 2013 is just braking a predetermined amount.

Yes, the vertical is the voltage. Pulse width modulation (PWM) is a method to control the average voltage going to a circuit under computer control. Longer on-time pulse widths equates to a higher equivalent DC voltage, for example, if the pulse on time and off time were equal (50% duty cycle), then the equivalent voltage would be 6 volts.

The RAM documentation claims the ITBM has an accelerometer but I don't think it does or its used secondary, I think the ITBM uses the amount of vehicle brake pressure be applied. This is the best way and how the elite aftermarket brake controllers did it, they taped the hydraulic brake line.

To support this, I can sit in my truck, select the ITBM scale in my cluster display, press on the brake pedal, the more I press, the higher the scale shows until I hit 100%. On my 2013, the PWM signal on the brake line is proportional to the pressure I am putting on the brake pedal. Doing the same in my 2015, I see the same proportional signal on the brake line, but instead of being scaled from 0 to 12 volts, it is scaled 0 to 7 volts. This is illustrated in the following graph;



You can see how the 2015 brake output is skewed but linear. The more brake pressure, the more output skewing. This is why I think it is a calibration value in the 2015 ITBMs. The 2013 ITBM output tracks equally with the amount of brake pedal pressure.

Accelerometer aside, the ITBM slider control is an override, it should provide the maximum brake output with respect to the gain setting, gain of 10 should provide 12 volts, a gain value of 5 would yield 6 volts.

 

[drittal]

So the connector may just be part of the problem for some of us.

 

[Hemifatboy]

In my 2015 manual it show 4 different settings in the evic for the brake controler depending on what type of brakes the trailer has , light electric , heavy electric, light electric over hydralic and heavy electric over hydralic , if that has anything to do with it

 

[15BlueStreak]

So does the dealer or Ram have an answer for this? I will check mine when I get it for test drive. Do they have to flash the itbm. This is going to be very frustrating if my new truck won't be able to tow my camper due to a faulty controller.

 

[BossHogg]

In my 2015 manual it show 4 different settings in the evic for the brake controler depending on what type of brakes the trailer has , light electric , heavy electric, light electric over hydralic and heavy electric over hydralic , if that has anything to do with it

I don't know much about electric over hydraulic. The difference between heavy electric and light electric is the amount of initial power that is provided to the electric brakes when the ITBM sees the brake input go active. It is a prelude to a braking action. After market controllers call it a boost level.

So does the dealer or Ram have an answer for this? I will check mine when I get it for test drive. Do they have to flash the itbm. This is going to be very frustrating if my new truck won't be able to tow my camper due to a faulty controller.

To my knowledge no one has received a fix for this issue. Every report from someone that took their vehicle in has received the same end answer, nothing is wrong and they never heard of the issue before. Well, it doesn't take much internet forum reading to see this is a popular issue. This along with the sampling of 2015 ITBMs I looked at belonging to colleagues at work, I believe this issue is on all 2015 ITBM and possiblely 2016s. I would love to find a 2016 and take measurements, if the issue is gone, then they recognized the problem and fixed it.

There is also a lot of confusion inserted into many of the threads from owners with pre 2015 modules reporting a working controller (???) to others saying they have the same or like issue with trailer braking.

RAM redesigned the ITBM for MY15. The only folks that will see the issue are ones that pull trailers with bigger brakes, for example, 12 inch electric brakes or electric over hydraulic braking. They require more voltage to function than a 5 inch brake. Likely why there are a number of successful reports on 2015 ITBMs.

What size electric brakes does your camper have? If the camper's brakes will lock up with less than 7 volts you will be OK. I don't have an issue with my 18 foot flat bed utility trailer but my 15K pound Montana fifth wheel, I need more than the 7 volts to get it stopped.

 

[cc rider]

Damn! Boss lives in Michigan. I was hoping he lived in a southern state where he would use his trailers year round. If anyone is going to figure this out it's him. We are both up north and getting close to that dreaded time of year. I have one more trip planned to lake George rv park in the Adirondacks for Columbus day weekend. Then they all close up. Me and the girl are taking the bikes in the toy hauler for some scenery. Hopefully the weather will be dry. Then that's it for heavy hauling for me. I was thinking about getting another controller for the trip. Otherwise , I'm playing with safety. I'm too cheap though. So if you guys don't hear from me after then, u know what happened and u can show ram this too!

 

[15BlueStreak]

Not sure what size brakes I have. That should be irrelevant. The controller should put out the right volts either way. I bet there will be a recall or tab soon on this once more people complain. There are a lot of these trucks on the road unsure of the amount of 15s but when I do a search on google for it there are not a lot of hits for this problem. So hopefully it's not vastly widespread. I pickup truck for test drive on Monday. You get yours back on Monday hopefully. I will report what I measure with my meter on Monday.

 

[cc rider]

Of course it's relevant. More voltage= more stopping power.

Not sure what size brakes I have. That should be irrelevant. The controller should put out the right volts either way. I bet there will be a recall or tab soon on this once more people complain. There are a lot of these trucks on the road unsure of the amount of 15s but when I do a search on google for it there are not a lot of hits for this problem. So hopefully it's not vastly widespread. I pickup truck for test drive on Monday. You get yours back on Monday hopefully. I will report what I measure with my meter on Monday.

 

[loveracing1988]

Of course it's relevant. More voltage= more stopping power.

I think he means it should be irrelevant as in it shouldn't matter what size brakes you have the brake controller should work.

 

[cc rider]

Ok sorry if I misunderstood

 

[15BlueStreak]

I think he means it should be irrelevant as in it shouldn't matter what size brakes you have the brake controller should work.

Yes that's what I was getting at. It's all good!

 

[15BlueStreak]

So I tested the integrated brake controller on my 05 f250 just now to have a comparison for when I test the ram tomorrow. What I found interesting is I only get 2.5 volts when the brake pedal is pressed at 10 gain. No trailer is hooked up to it. Push slider over and get 12 volts. I know my trailer brakes work when towing with this truck. Not trying to muddy the waters here but just a comparison to another manufacturer brake controller.

 

[drittal]

So my local dealership stinks...

Made an appointment for them to at least look at it and get it logged.

It didn't even get that far.

My wife took it in and my father was there to pick her up. She tried to explain, but didn't really know. So she called me and handed him the phone. I told how it takes 2x the gain as a 2012 Ram.

We went rounf and round until he tried to put me on hold, I hung up. I was so mad i didnt even have the sense to ask about the holtage differences. Wife and father left without leaving the truck. My wife said he was rude in person.

 

[cc rider]

Lol! You think that's bad. I've been to dealer several times for the dumbest problems and they can't get them right. I think I'm going to start a " who has the worst dealer" thread when I'm done getting my issues fixed. Why did you edit the post by the way? I thought the phone conversation was funny. Should have left it in There.

 

[drittal]

I posted when I was still upset.

I just got home and talked to my wife and father. The service guy wasn't putting me on hold when he said hang on...

He was handing my wife back her phone because she had grabbed our keys and told him their services were no longer needed.

He honest to God told me you can't compare trailer brakes on a diesel truck to trailer brakes on gas truck.

 

[Hootbro]

No way I would send my wife in with my truck to explain an issue like this and expect results.

 

[drittal]

No way I would send my wife in with my truck to explain an issue like this and expect results.

I had explained the issue when I made the appt. Then she called me so I could explain to him my issues. He was instantly confrontational, rude to my wife and father, and showed no interest in addressing the issue other than to insinuate that I was an idiot.

 

[15BlueStreak]

The truck I am purchasing has the same issue with the voltage. Just measured it tonight. I have searched on Google and there are a lot of people complain about these controllers all the way back to 2011 or 2012. Maybe it's just a matter of preference between drivers but a lot of people are not satisfied with the controllers output. Most have resulted to going with aftermarket controllers. I plan on getting a tekonsha to put in my new truck. It seems ridiculous but I think I could trust it more. I like everything else about this truck so it's not a deal breaker if the brake controller is the only sub pat thing. I just wouldn't have got a truck with it if I knew they were not up to the task. In one of the cummins forums a person actually noted that a tech from dexter axle has seen that the factory controllers are not putting out the juice to help protect the trucks? Thus people switching to aftermarket.