GM Integrated Brake Controller

[drfife]

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 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. 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.

[Rustic Eagle]

Originally Posted by drfife

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

You wouldn't think it would..., but I'm not familiar with the new TV OEM integrated brake controllers and how they work (compared to a Prodigy, etc.). One would think that the TT brakes would have a controlled application ramp before the TV's brakes.

I'm sure members that use these integrated units will chime in.

Bob

[Panhead]

Our 2007 Ford F250 has their version of the integrated brake controler and it works perfectly, I would say that if there is a delay in applying breaking power to the trailer that there is a problem. I set ours at 8.5 on the gain. I'm sure a GM owner will chime in here and give his experience.

Good luck in working out this problem

Steve

[dmax_83]

I couldn't be happier with mine, I have the gain set at 6.5 and it slows everything down so smoothly. I have certainly never experienced a delay, in fact last summer I had to do a panic stop and I was very impressed with how well it did. Sounds like you should make an appointment with your dealership. BTW, are there any trouble codes being thrown?

[drfife]

Originally Posted by dmax_83

I couldn't be happier with mine, I have the gain set at 6.5 and it slows everything down so smoothly. I have certainly never experienced a delay, in fact last summer I had to do a panic stop and I was very impressed with how well it did. Sounds like you should make an appointment with your dealership. BTW, are there any trouble codes being thrown?

No codes picked up on my Scangauge II.

I guess I'll be making a trip to the dealership.

I Need to tow the trailer next weekend about 50 miles round trip for a camp out with my local camping group.

[dmax_83]

Sorry I couldn't be of more help. Saw your post over on DP as well. If you cycle through the DIC there is a screen that shows the gain setting and the amount that is being applied to the trailer brakes, when you hit the truck brakes is that screen show a delay as well?

[drfife]

Originally Posted by dmax_83

Sorry I couldn't be of more help. Saw your post over on DP as well. If you cycle through the DIC there is a screen that shows the gain setting and the amount that is being applied to the trailer brakes, when you hit the truck brakes is that screen show a delay as well?

No, when my wife pressed hard on the bake pedal, it immediately registered 8. A couple of seconds later the wheel I was spinning manually would stop.

Very strange.

I can't find anyone else having a similar problem or symptom with their GM ITBC.

Why can't I have a normal problem?

The delay explains the numerous Hensley bumps I've experienced.

I only experienced it a couple of times with my Suburban and BrakeSmart controller on 60K+ miles towing. I've had at least a half dozen bumps in 1500 miles with the new truck.

[dmax_83]

Yeah, it sounds like something is defiantly not right with your IBC. If it makes you feel any better my duramax has had some shop time for warranty work too.

[drfife]

Originally Posted by dmax_83

Yeah, it sounds like something is defiantly not right with your IBC. If it makes you feel any better my duramax has had some shop time for warranty work too.

I've been lucky with my 2002 K2500 Suburban and 2011 GMC Yukon Denali. Neither had any warranty issues.

Guess the 3500HD's ITBC is really just a minor problem.

[3Pillons]

Does the integrated controller provide proportional breaking? If the truck and trailer were sitting still, it wouldn't "feel" any inertia and think it didn't need to activate the trailer breaks. I might try "gingerly" testing the system while rolling in a safe location before getting too concerned. Just a thought, please let someone smarter than me chime in.

[Rustic Eagle]

Originally Posted by drfife

snip.......I guess I'll be making a trip to the dealership.....snip

I agree, sounds like an issue within the ITBC unit itself.

I have run across a couple GM TSB's on the ITBC, but I believe they were "connector" related issues.....,there wasn't any reference to the condition you described.

Bob

[drfife]

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.