View Full Version : Factory Brake controller on GMC 2500HD

07-28-2008, 04:00 PM
I will be picking up our new Landmark Augusta sometime later this week (yea!). I am new to 5th wheeling and need help determining the proper trailer gain setting on my factory trailer brake.

My 2008 GMC 2500HD Duramax owners manual states that I need to drive about 20 mph while towing and apply the brakes. I am supposed to set the output gain just under trailer brake lock up. The problem is, the dealer is located on a busy highway and then I have to go straight to the Capital Beltway.

The dry weight of the Landmark is a tad over 12500 lbs and my truck around 6500 lbs.

Can anyone recommend the proper setting until I get a chance to test and properly set it on an isolated road?

I assume I will use the maximum setting of 10.0

Thanks, John

07-28-2008, 05:15 PM
Don't know squat about GM brake controller. My Ford integrated controller always needed to be maxed out no matter what I hauled:confused:

Pulling different trailers everytime I hook up when I hook up to a trailer I get the initial setting in the yard at very slow speeds and fine tune as I go if needed. Realisticly you really can't pull out on the road and start slamming on brakes at 20 mph unless you live out in the boonies but you should be able to get close in the dealers lot in a small space.

Here's how I do it and I'm using a Tekonsha Prodigy for now.

I turn the gain down from it's last setting.
I creep forward engaging the trailer brakes and adjust the gain up until I feel the brakes apply.
Now stopped and holding the trailer brakes on, I ease forward and the trailer brakes should lock and hold the trailer within a few feet.
I now pull forward to about 5 - 10 mph and hit the brakes, you should just barely feel the trailer brakes come on first.
Now I know I am close and feel safe to leave. I adjust slightly at any traffic light I come to on the way to the insterstate as needed.
You don't want the trailer brakes to lock under hard braking or the trailer to pull you backwards a foot (and they will) either everytime you stop, nor do you want to feel like it's pushing you every time you stop.

Hope this helps, congrats on the new Landmark(DROOL). Mike

07-28-2008, 09:37 PM
I have a 2007 GMC 2500HD Duramax with the factory brake controller. I had it set at 7 for my 24' enclosed car hauler. When I put the 5er on (BC 3355RL) and put on the brakes, the 5er nearly pulled me backwards at 7. Turned the controller down to 3.5 and it worked just fine. Hope this helps. I find it best to find an area where you can test to fine tune it. Good luck with the new unit!

07-29-2008, 06:12 AM
I have the 2008 GMC 2500HD Duramax with intergrated controller as well. I have it set at 5.5 and the brakes work very smoothly at that setting for me. I pull a Bighorn 3600RE.

07-30-2008, 06:15 PM
I have the 2008 GMC 2500HD Duramax with intergrated controller as well. I have it set at 5.5 and the brakes work very smoothly at that setting for me. I pull a Bighorn 3600RE.

Thank you for the replies. I think I will set it at 5.5 until I can fine tune it.

How much does your Bighorn 3600RE weigh?


08-06-2008, 08:25 PM
After a test run and driving on the road I got a chance to tweak the IBC. I started out with 5.5 and ended up at 6.0. Worked great.

Thanks again for everyone's help


08-07-2008, 12:28 PM
How much does your Bighorn 3600RE weigh?


Sorry John for the slow response. Been gone a few days. My 3600RE Bighorn weighs in at around 14,250 the way I currently have it loaded. Since you have the Landmark and it is slightly heavier no doubt you will need a higher setting.

On a side note... I love my GMC 2500HD with the Duramax and Allison trans.. Was in the mountains last week and going down some 8% and 11% grades that were 2 - 4 miles long and never touched the brakes. Drop it in manual and use the push button shift up and down. Then on the upside of the grades I was passing cars and pickups that were struggling to keep up any speed and they would just stare as me and my Bighorn rolled by them uphill. I had my display set to show the transmission temp and only once did it ever come close to showing what you might call hot, about 210 was the highest, normally runs 185 to 200 even in mountains.

09-25-2008, 09:55 PM
I have a 2008 GMC with the built-in brake controller and
I had a older Tekonsha Brake Controller ( Herky Jerky),
you will most definately not have that with this set up.
I do find that I have to turn the gain way up in comparison
to my old set up. I am adjusting my brakes
and that might make a difference. I would like to feel a
little grab so I know they are working.

10-20-2008, 11:54 AM
I run my IBC at 7-8. This is pulling a 9500 lb Sundance with my 07.5 Chev 2500 HD. I wouldn't worry too much about the initial setting as it is very easy to adjust while on the fly. If the brakes grab too much, just back it off a number or two. If you can't feel the trailer brakes at all, bump the number up a little. The procedure is very easy to get the hang of. My factory IBC works about the same as my Tekonsha Prodigy. Both are good units, but I like not having the 'clutter' of an brake controller mounted under my dash.

10-20-2008, 11:27 PM
In my 08 Chev with the IBC and the 3110DS I run mine at 7.5. I like mine stiff so if I need it it's there. We live in a rural area and not much stop and go stuff to deal with. The only time I lowered it was driving through Lake Havasu City. I lowered it to 6 to keep the stiff stops to a minimum through the gazillion lights. I weigh about 21K fully loaded.

11-06-2008, 01:46 PM
I also recently bought a new Chevy 3500HD and was curious about the IBC, my 2005 Chevy 2500HD had a prodigy. Thanks for the information.

11-06-2008, 06:11 PM
Hey there, we have an 08 3500, with a cyclone 3950, I have been towing with the brake controller set at 4-5, plenty of stopping power, actually the best and easiest brake controller I have ever used>>>>hope this helps...remember this controller takes in account how hard you hit the brakes, meaning it does not give pull braking power at first, its progressive, you can see your dash and the power output as you drive, the computer will recognize when you plug your trailer in.

Delaine and Lindy
11-06-2008, 06:57 PM
We have a 2008 Chevy 3500 and have the IBC it will work fine with electric brakes set it at 5.5. We now have a Mobile Suites and it came standard with Disk Brakes, electric over hydraulic. The IBC isn't compatible with electric over hydraulic Disk Brakes, so had to install the Prodigy. Wouldn't trade the Disk Brakes for the IBC. GBY....

11-06-2008, 11:19 PM
You have been receiving some great info from several posters, but just to clarify.....everyone (including me) is giving you advice on what setting to use. As you can see, everyone has a number that seems to work for them. There are many factors that could contribute to these wide variety of settings. Every trailer has brakes that have been manually set up differently, as well as different weights, different resistance of the manufacturers wiring, atmospherics and even some small differences between the IBC's themselves. Pull a number out of the air and try that. If it doesn't work well enough, then it is very easy to adjust while you are driving!
Another great factor that seems to go unmentioned so far, is the factory IBC also gives you some degree of protection for anti skid! When your vehicle ABS senses pending wheel lockup, it decreases the voltage to your trailer slightly (via the IBC) to preclude trailer wheel skid. A Prodigy can't do that!

11-07-2008, 06:18 PM
After several trips, I changed the IBC setting to 7.0 Slow moving stops can be a little more abrubt but higher speed stops are much better. The brakes tend to lock up for me if I go any higher.