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Brake controller issue when towing 5er

3.2K views 11 replies 8 participants last post by  Hook'em_Horns!  
#1 ·
My 2016 GMC 3500 HD seems to have an issue with the brake controller. I can manually squeeze the levers on the dash controller, and my RV 5th wheel brakes work, BUT when I push my brake pedal, my RV technician told me my RV brakes are not working. The RV technician took infared temperature readings on the RV rotors immediately after a 4 hour tow and ALL were 74 degrees, when my front truck rotors were 200 degrees. Anyone else experience anything like this? I have an appointment at GMC garage in a week, but any comments are welcome.
 
#2 ·
Subd for some education.
 
#3 ·
What power is the brake controller set at? Mine is set at 7.5
 
#5 ·
The RV technician took infared temperature readings on the RV rotors immediately after a 4 hour tow and ALL were 74 degrees, when my front truck rotors were 200 degrees.
Rotors would be EOH.

OP, when you apply your brake pedal, does your 3rd brake light work too?
 
#7 ·
If your truck senses electric over hydraulic brakes, sitting still with just brakes pedal applied, your pump will not be running. This is to prevent burning up your pump while sitting still. If you squeeze the manual brake controller, your pump will run. If it doesn’t run with the manual controller applied you have a wiring problem.

If you want it to apply sitting still with just the brake pedal pushed, then you can wire in a known good magnet set a against a piece of iron. When the brake controller senses the resistance in the magnet it will think you have regular electric type brakes. But if you get stuck in stop and go traffic your pump will not last as long.
 
#8 ·
Adjusting electric brakes

It is my experience that braking efficiency is vastly different rolling at 70 mph as opposed to 25 mph in a lot or neighborhood. When I tow my 16K lb fifth wheel, I generally have to set the in-dash controller gain of my 2016 Chevy to at least 8 at highway speeds. When I'm going up and down a lot of hills, normally, I set it higher. To set, use the brake controller only, not your vehicle brake combination, so the you will feel how much braking performance you have. Adjust the gain as necessary. The same goes for my car-hauler trailer, which I've used more for moving interstate. In town, I have to lower the gain to stop locking up the brakes and dragging the tires, and at freeway speeds raise the gain to feel the braking necessary. Every load, trip, truck, and trailer will be different and require monitoring and adjustment for optimal braking performance. This is not something you can set at 25 mph and forget about it. When the in-dash controllers came out the consensus of most, IMO, was if your controller works with your trailer brakes at whatever setting, it is OK. Some had trouble and could not get enough braking power out of their controller. This could be as said before about the computer sensors and different trailer brake systems.
 
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#9 ·
When you show up at the garage, take your trailer with you. You are asking them to look at your truck and it's the trailer that shows the problem. Without the trailer, they won't be able to confirm your complaint with the truck.
 
#10 ·
Took some of your advice. I raised my setting to 8.5. That was the ticket. I could now feel the trailer assist. I did the 20 mph set, and 9.0 is my new setting. Thanks for the input.
 
#11 ·
Setting at 9 is OK for highway speeds but you need to be aware your brakes may lock when you pull into a fuel station or RV park at that high a setting. Listen for sounds of brake locking. Around town I'm set at about 7 to 7.5. You are almost maxed out on your gain. As your trailer brakes wear, braking efficiency may diminish. Then you may need to look into trailer brake upgrades such as disc brakes. Good luck.
 
#12 · (Edited)
Then you may need to look into trailer brake upgrades such as disc brakes.
I think he's already there.

Everything you've described about gain and fast and slow speeds, sounds like the antiquated 30+ year old controllers of the past....not the modern proportional controllers of today.

You should be able to adjust for the weight you're pulling, and forget 'bout it....fast, slow, or in panic stops at any speed.

The IBC has always seemed like a factory fix looking for a problem....and have all been problematic and testy in their performance.
The Prodigy series was/is highly perfected and never a problem. Lifer warranty, they never hesitate to fast ship a replacement, when the slightest of issues might develop...which are rare.

Not sure how GM thought they could make a better mousetrap, or why they thought we needed one.

Oh, and mine....goes to 11. marx