2024 Brake controller Problems

UWSkier · September 20, 2023

Same here. New module arrives at dealer Monday and should get it installed next week sometime.

Salzette · September 25, 2023

Ok, just hitched up and towed for the first time…and even without solar I had the disconnects. Since I was just taking it in for a maintenance issue, I just turned the battery off and it solved the problem. But…Thursday we leave for a trip and since I have a 12v fridge I don’t really want to turn the battery off. Can’t get the fix done before then…what’s my best course of action? Any recommendations?

lurker_007 · September 25, 2023

How far of a trip are you taking? If you plug the rv in the day before and let the fridge and its contents get good and cold well before your trip, it will essentially act as a cooler when not powered on. Or do you have a propane option? I have another older travel trailer, the fridge only works on shore power. I’ve camped with it several times by letting it all get cold for a few days before we left. The day of the trip it will stay cold well over 9 hrs of driving until I get to the campground.

UWSkier · September 25, 2023

3 hours ago, Salzette said:

Ok, just hitched up and towed for the first time…and even without solar I had the disconnects. Since I was just taking it in for a maintenance issue, I just turned the battery off and it solved the problem. But…Thursday we leave for a trip and since I have a 12v fridge I don’t really want to turn the battery off. Can’t get the fix done before then…what’s my best course of action? Any recommendations?

How hard is it to get to the wiring on your trailer? I wired in a diode on my black 12v power feed line where it comes into the RV so that power can only flow from the truck TO the RV but not in reverse. After doing that, I read 0v on the 12v pin of the trailer when it's sitting disconnected from the truck. It shouldn't take more than 20 mins if you have decent access to the wiring.

Salzette · September 25, 2023

4 hours ago, lurker_007 said:

How far of a trip are you taking? If you plug the rv in the day before and let the fridge and its contents get good and cold well before your trip, it will essentially act as a cooler when not powered on. Or do you have a propane option? I have another older travel trailer, the fridge only works on shore power. I’ve camped with it several times by letting it all get cold for a few days before we left. The day of the trip it will stay cold well over 9 hrs of driving until I get to the campground.

Don’t have the propane option, but you make a good point - it’s a short trip, about 2hrs. So I think if I have everything good and cold I’ll be fine with the battery disconnect off. I can always throw a few reusable ice packs in if I’m really worried about it. I’m so used to the fridge running on the drive I missed the obvious that it’ll stay cold that long.

It’s our last trip this year, so I’ll have the dealer take care of the fix (hopefully) we’ll before I have to tow again.

lurker_007 · September 25, 2023

Keep in mind that the battery quick disconnect only disconnects the 12v power going to the coach from the battery, but not from the truck to the battery or from the battery to the truck. That was the first thing I tried when troubleshooting after reading the bulletin. You’ll need to disconnect the negative lead from the battery to actually prevent the battery from back feeding. Or do as the others have suggested and wire in a diode. Not sure what timeline you have but I couldn’t get one local and had to order one on Amazon. If you can’t get one and wire it in before your trip, turning the battery disconnect will only kill power to your refrigerator but still give you the error message and turn off your brakes.

Jettech1 · September 26, 2023

1 hour ago, lurker_007 said:

Keep in mind that the battery quick disconnect only disconnects the 12v power going to the coach from the battery, but not from the truck to the battery or from the battery to the truck.

I was hoping someone would clear that up. You are absolutely correct, the only way to turn the 12v fridge off is to shut it off with the knob inside the fridge or unhook the battery. The battery disconnect does not turn your fridge off.

lurker_007 · September 26, 2023

4 minutes ago, Jettech1 said:

I was hoping someone would clear that up. You are absolutely correct, the only way to turn the 12v fridge off is to shut it off with the knob inside the fridge or unhook the battery. The battery disconnect does not turn your fridge off.

The battery quick disconnect will cut power to the 12v fridge and everything else inside the coach that runs on 12 volt ie. the interior lights, vent fans, water pump etc. The point I was making is that the brake issue is due to the trailer battery back feeding into the truck. The battery will still back feed into the truck even with the quick disconnect turned on because it only cuts the circuit to the internal 12v system of the rv. The running lights, brakes, and battery will still be powered and connected to the truck which wil cause the module to shutdown and give you brake issues.

Salzette · September 26, 2023

10 minutes ago, lurker_007 said:

The battery quick disconnect will cut power to the 12v fridge and everything else inside the coach that runs on 12 volt ie. the interior lights, vent fans, water pump etc. The point I was making is that the brake issue is due to the trailer battery back feeding into the truck. The battery will still back feed into the truck even with the quick disconnect turned on because it only cuts the circuit to the internal 12v system of the rv. The running lights, brakes, and battery will still be powered and connected to the truck which wil cause the module to shutdown and give you brake issues.

If I’m understanding the issue that causes the problem correctly, can it be solved simply by letting the battery run down some before it’s time to hitch up and go? The fridge will put some drain on the battery as well on its own, and if it’s unplugged from shore power for, say, and hour or two, before travel…it shouldn’t be getting enough charge from the truck to be fully charged while on the drive? I thought I was understanding that the issue only occurred when the battery became fully charged and would back feed to the truck, but I’ll be the first to admit my battery/electrical knowledge is not my area of expertise. Oddly, the disconnect seemed to work today, but it was only about a 20 minute drive so that could’ve been a fluke.

edit: I also do NOT have solar, so the only charge the battery would get while driving is from the truck.

Edited September 26, 2023 by Salzette

jonpc · September 26, 2023

I got the updated part installed last Thursday and removed the previously installed diode and did a 200+ mile drive with ZERO issues. Looks like the updated brake controller finally fixed the issue.

For the sake of everyone reading, there were 2 solid solutions that worked without issue, and 1 potential solution.

Solution 1: Installed Diode on the 12v charge wire (Black) from the Truck to trailer. This prevented all back feeding and worked for long drives without issue.

Solution 2: GM installed new Brake Controller. Took them less then 1 hour for the install. They did have to order the part which took a couple days. Was fully covered by warranty.

Ideal Alternative Solution until you get GM installed updated Brake Controller: I purchased the Curt Echo Mobile Bluetooth brake controller. This is put inline with the trailer plug and bypasses the trucks brake controller. You can control sensitivity and gain using a mobile app, and can even have a manual brake button on the phone. I drove 2k+ miles using this setup. I was very annoyed that I needed to use this adapter on a brand new 2024 3500 GMC, and lost the ability to control gain and manual braking with the in-truck controls, but it was better to have reliable brakes when I was going through a lot of mountains.

Potential Solution: I attempted a drive with all 12v accessories turned on in the trailer while driving. Fans, Lights, Fridge, etc. This was an attempt to keep the charge on the batteries low enough that the back feeding would not occur. It worked for about an hour before the 550watts of solar was charging faster then the usage. This may be a viable solution for trailers with little or no solar.

Jettech1 · September 27, 2023

On 9/25/2023 at 9:49 PM, lurker_007 said:

The battery quick disconnect will cut power to the 12v fridge and everything else inside the coach that runs on 12 volt ie. the interior lights, vent fans, water pump etc. The point I was making is that the brake issue is due to the trailer battery back feeding into the truck. The battery will still back feed into the truck even with the quick disconnect turned on because it only cuts the circuit to the internal 12v system of the rv. The running lights, brakes, and battery will still be powered and connected to the truck which wil cause the module to shutdown and give you brake issues.

Apparently it's different with different manufacturers. On our Grand Design the battery disconnect does not turn power off to the fridge.

madweazl · September 27, 2023

15 hours ago, Jettech1 said:

Apparently it's different with different manufacturers. On our Grand Design the battery disconnect does not turn power off to the fridge.

This is true of most units with an inverter that powers a residential fridge. I can disable both giggy boxes but still have to turn off the inverter if I want to shut down the fridge. It's a wonder trailer wiring works at all LOL.

ssgballistics · September 29, 2023

Took my truck to the dealership on Wednesday. The service writer instantly acknowledged that they were tracking this issue. They ordered the replacement module, but don’t have any estimate on when they will get it. Told me that they hadn’t received any parts orders this week due to the strike.

Slsl123 · September 29, 2023

I installed a switch to shut off my solar panels and that took care of my brake controller issue. Unfortunately now my solar panel won’t charge my batteries when I’m towing.