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GM Integrated Trailer Brake Controller

Discussion in 'Towing & Trailer Tech' started by drfife, Apr 23, 2012.

  1. drfife

    drfife New Member

    I have a 2012 GMC Sierra 3500 HD SRW Duramax with a GM integrated brake controller. I tow a 9,000 lb travel trailer. I've logged 1,500 miles towing since January 2012. I use a Hensley Arrow trailer hitch.


    I set the gain on the brake controller at 8.0 after following the set-up instructions in the owners manual.


    Last weekend I had to perform a panic stop at 40 mph to avoid collision after a car turned left across my path. The force of the stop resulted in the shearing of two of the Hensley shear bolts on the left strut. This occurs when the truck decelerates much faster than the trailer. I repaired the Hensley at the campground and our return trip was uneventful.


    I adjusted the trailer brakes today. Very little adjustment was required. To verify they were functional I had my wife apply the brake pedal. There was a 2 to 3 second delay from application of the brakes in the truck to braking on the trailer wheels. If the manual lever was activated on the brake controller, the brakes applied instantly.


    Is it normal to have a delay from truck braking to energizing the trailer brakes?


    I have noticed that the trailer bumps the tow vehicle much more than my previous vehicle and brake controller.


    I have towed the same trailer with an '02 K2500 Suburban with a BrakeSmart brake controller for many years and many miles. The BrakeSmart provided multiple adjustments to provide optimal, smooth braking. The truck and trailer truly braked in harmony.


    The GM controller only has a gain setting.


    Do I have a problem that needs to be checked by GM? Should I install a more sophisticated brake controller for my safety?


    Thanks in advance for your advise and suggestions.
  2. drfife

    drfife New Member

    I have a meeting scheduled with a local GMC dealer to check the ITBC.


    The tech requested I bring the truck with trailer and he'll check the output and performance with his scanner in real time with the trailer attached.


    Will keep you posted.
  3. I am interested in the result of your meeting as well. I will be watching!
  4. carbon black

    carbon black New Member

    I'm also interested in knowing the results of your meeting as I also ordered the integrated trailer brake controller as well on my 2012 GMC Sierra 1500 - Has I still haven't taken possession of my truck - so I don't know how the trailer brakes will react on my 5,500 lb travel trailer
  5. Blackmatter

    Blackmatter New Member

    I have towed with the intergrated trailer break and a trailer that ways about the same as yours. I don't have the hensley i have the propride hitch and from what i can tell with mine i don't have a delay like that.
  6. drfife

    drfife New Member

    I took my truck with trailer to my local GMC service center. A service tech, that is an experienced RVer, took a test drive with my truck and trailer. After multiple gain adjustments, we agreed that 8.0 felt best and most secure.


    We then hitched my trailer to a new 2012 GMC Sierra 2500HD CC SB Duramax which is similar to my truck, except mine is a 3500 and has the Z71 package. We took it out on the same route and performed the same tests. It too had the best braking with my trailer with the gain set at 8.0.


    I do not know why, but the brake pedal felt "mushier" and had more travel than my 3500.


    The braking response with both GM trucks with the ITBC were similar, but not as smooth as my previous BrakeSmart controller. The GM ITBC only has gain adjustment. The BrakeSmart provided additional adjustments like initial brake constant and power factor, in addition to gain.


    The tech felt that I had become accustom to a more customizable controller. The GM controller is acceptable to most people. He could not explain delay I observed with the brake pedal vs manual lever when stationary. The system is hydraulic brake fluid pressure based. He felt that additional motion sensors do not activate immediate signal to brakes if stationary. He has not had to repair an ITBC before.


    They offered to disable the ITBC and install the brake controller of my choice at no charge. I will play with the current system and decide if I think I'd be better off with a different controller. Too bad BrakeSmart is no longer being produced. That would be my first choice.


    A friend performed the same test with his GM truck with ITBC and had the same result. When the trailer wheels are off the ground and spinning, the manual controller works instantly and a 2-3 second delay when the brake pedal is depressed.


    The service manager and techs at Classic GMC of Carrollton treated me with respect and Were very friendly and helpful.


    My conclusion: The ITBC in my truck functions as designed. It is good enough to make most people happy. GM could take a lesson from BrakeSmart and increase the available adjustments and improve their ITBC. They also should provide better information to the consumer of how their current product functions. Even the techs are in the dark.
  7. qepv25a

    qepv25a New Member

    It sounds like the controller is a "timed based controller." My prodigy p2 is inertia based. I had a time based before and it did what yours is doing. Have gm disable it and get a good aftermarket cintroller. Bob IMHO
  8. steved

    steved Former Member


    The brake controller is a lot like a BrakeSmart controller...it senses brake pressure, its not a inertia-based system. In other words, the harder you slam on the brakes; the harder the (IBC) controller applies the trailer brakes.

    I didn't understand this until today, I finally hooked up two trailers, and it worked flawlessly.
  9. steved

    steved Former Member



    I was thinking about this the other day, but have you traced all the trailer wiring out and made sure all the connections are good? I have found many trailer brake wiring systems held together with scotch-loc connectors (insulation piercing deals) and find they lose connection from corrosion.

    I took my own 5vr, removed the scotch-locs and solder each connection solid, and heat shrinked everything. The difference in braking was night and day, the brakes were more responsive (as in instantaneous), and they applied harder (with less controller input). I have since did this same solder job on every trailer I own, it made an improvement on every single one. The 5vr wouldn't even slide the wheels when manually applying the brakes, afterwards they would lock up before the actuator was even 25% engaged!

    Don't forget about the trailer connector itself, they corrode too and also need replacing just because of broken wires from flexing.

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