2024 Brake controller Problems

Salzette · January 30

Does anyone know for sure if the trailer brake controller issue causes an error code to be stored? My service department (which is a bit of a drive away for me) is trying to tell me I have to bring the truck in so they can see for sure it has an error code before ordering the part. But as I understand it there isn’t an error code stored, and the trailer simulator won’t replicate the problem anyways…so it feels like a super wasteful trip to the dealer for me. I’d like to be able to know for sure when I call back so I can tell them not to waste me an hour drive each way and tell them to just order the part and call me when it’s in…

Edited January 31 by Salzette

UWSkier · February 1

I don't believe my dealer required an error message before ordering and installing the updated (older) part.

DC13 · March 5

Having the same problem on my 24 GMC 3500. There is an updated bulletin from Sept 23 to address this where GM will replace the Trailer Brake Control Module... and yes it's from the solar panel charging the batteries higher than the voltage of the truck batteries.

#23-NA-149

Hope this helps

DC13 · March 5

MC-10243754-0001.pdf

UWSkier · March 5

I've towed several times post-update and haven't seen a single problem.

Rick_ · March 17

On 3/5/2024 at 11:10 AM, DC13 said:

Having the same problem on my 24 GMC 3500. There is an updated bulletin from Sept 23 to address this where GM will replace the Trailer Brake Control Module... and yes it's from the solar panel charging the batteries higher than the voltage of the truck batteries.

#23-NA-149

Hope this helps

It sounds like there are several issues going on. I have the "Check Trailer Connection/Check Trailer Brakes" on my 24 3500HD. It was happening since the first time I hooked up last September but then occurred myriad times on a trip I was just on. I found this thread and read about the solar battery charger controller thing and figured I'd turn it off at the disconnect the next time it happened. Sure enough, the batteries charged back up and the messages returned. I pulled over and turned the charger controller disconnect to off and the issue cleared for the most part. The part that didn't clear up was the Check Trailer Connection right after start up. That went away immediately and the trailer brakes worked fine the rest of the trip.

I am going to contact Victron as the SmartSolar Charge Controller doesn't seem to go into float and the battery voltage is above 14v after they are charged fully. The float voltage is set to 13.80v so I need to have Victron explain to me how to properly set this little gizmo up. The cool thing about the controller is that it records charging history and I went back a few days to verify the messages were happening after the batteries were fully charged. Then, when the messages came on the final time, I grabbed this screenshot of the solar voltage and battery voltage to illustrate what is happening. You can also see where I turned off the controller.

Edwin Grundy · March 22

I have a 2024 GMC 2500 HD and tow 10,000 lb man lift-total load with trailer 12,500lbs. The trailer has hydraulics to tilt the trailer and a lead acid battery to power this. We do not have a solar panel attached to the system. We are having a problem with our electronic controller. It intermittantly posts a message "check trailer wiring" and during this time there are no trailer brakes. We have towed the same trailer with two other vehicles and do not have a problem. We have had the trailer checked and cannot find a wiring problem. GMC has refused to put me into contact with a regional service tech that has technological knowlege regarding this subject. Some of the online posts that we have read state that solar chargers can and input higher voltage than the tow wehicle battery voltage causing interfearance with the controller. As stated above we do not have a solar charger, but the trailer battery does have a higher voltage reading than our tow vehicle, and we are experiencing the same problems. My question is what might happen if ther battery on the tow vehicle becomes slightly run down, the truck starts but now the voltage in the tow vehicle is less than the battery in the trailer. Does this mean that there could be brake malfunction? This is a severe safety issue. We have been able to eliminate the warning message by pulling the the trailer charging fuse in the vehicle fuse block (#84). We have also been able to eliminate the message by disconnecting the emergency brake positive lead from the trailer battery which eliminates the triler emergency brakles. Both of these solutions indicate that GMC has a problem with their controller. GMC promotes their trucks as GMC grade Professionsal Grade. You would think that their Professional Grade engineers would be aware of the different trailer types and wiring configurations when they designed the electronic controller. Apparently not as they refuse to admit that they have a problem. I urge everyone to file a complaint with the NTSB before someone is killed or injured as a result of a faulty controller.

Rick_ · March 25

On 3/22/2024 at 3:09 PM, Edwin Grundy said:

I have a 2024 GMC 2500 HD and tow 10,000 lb man lift-total load with trailer 12,500lbs. The trailer has hydraulics to tilt the trailer and a lead acid battery to power this. We do not have a solar panel attached to the system. We are having a problem with our electronic controller. It intermittantly posts a message "check trailer wiring" and during this time there are no trailer brakes. We have towed the same trailer with two other vehicles and do not have a problem. We have had the trailer checked and cannot find a wiring problem. GMC has refused to put me into contact with a regional service tech that has technological knowlege regarding this subject. Some of the online posts that we have read state that solar chargers can and input higher voltage than the tow wehicle battery voltage causing interfearance with the controller. As stated above we do not have a solar charger, but the trailer battery does have a higher voltage reading than our tow vehicle, and we are experiencing the same problems. My question is what might happen if ther battery on the tow vehicle becomes slightly run down, the truck starts but now the voltage in the tow vehicle is less than the battery in the trailer. Does this mean that there could be brake malfunction? This is a severe safety issue. We have been able to eliminate the warning message by pulling the the trailer charging fuse in the vehicle fuse block (#84). We have also been able to eliminate the message by disconnecting the emergency brake positive lead from the trailer battery which eliminates the triler emergency brakles. Both of these solutions indicate that GMC has a problem with their controller. GMC promotes their trucks as GMC grade Professionsal Grade. You would think that their Professional Grade engineers would be aware of the different trailer types and wiring configurations when they designed the electronic controller. Apparently not as they refuse to admit that they have a problem. I urge everyone to file a complaint with the NTSB before someone is killed or injured as a result of a faulty controller.

I took my truck in last week for the Trailer wiring messages and they replaced the brake controller with the updated version straightaway. There was a code stored, C114, that affirmed the issue I was experiencing.

One thing you can watch is flip the message center to Trailer Brake and watch to see if it the "bar" is grayed out or illuminated when the messages are appearing. Grayed out means the trailer brakes won't apply and illuminated means they will apply.

Tracker48 · March 27

Does anyone know what month build this was rectified. Or if it has been rectified at all. I have a 24' 2500 that was built in Jan. but haven't had a chance to pull my camper yet. And was just wondering if I should worry.

PaulBeck · April 17

If you’re having brake controller issues, check out this bulletin. Updates Sept 2023.

https://static.nhtsa.gov/odi/tsbs/2023/MC-10243754-0001.pdf

chopjaw · May 11

On 1/30/2024 at 6:13 AM, Salzette said:

Does anyone know for sure if the trailer brake controller issue causes an error code to be stored? My service department (which is a bit of a drive away for me) is trying to tell me I have to bring the truck in so they can see for sure it has an error code before ordering the part. But as I understand it there isn’t an error code stored, and the trailer simulator won’t replicate the problem anyways…so it feels like a super wasteful trip to the dealer for me. I’d like to be able to know for sure when I call back so I can tell them not to waste me an hour drive each way and tell them to just order the part and call me when it’s in…

I was also in the same boat concerning the trailer error code. I took my 24 3500 DRW to the stealership and they pulled the code. Come to find out that the code does not show up on the Banks iDash. Talking to the service guy, the Banks wont pickup the communication code.. Weird.... But they pulled the C code and replaced the module, did an software/firmware update to the truck and did the tailgate recall. Suprisiingly, it was done in a day...

newdude · May 11

2 hours ago, chopjaw said:

I was also in the same boat concerning the trailer error code. I took my 24 3500 DRW to the stealership and they pulled the code. Come to find out that the code does not show up on the Banks iDash. Talking to the service guy, the Banks wont pickup the communication code.. Weird.... But they pulled the C code and replaced the module, did an software/firmware update to the truck and did the tailgate recall. Suprisiingly, it was done in a day...

That's because it likely can only pull "P" codes so powertrain (engine/transmission) DTCs.

chopjaw · May 11

Makes sense.

chopjaw · May 11

On 3/27/2024 at 4:18 PM, Tracker48 said:

Does anyone know what month build this was rectified. Or if it has been rectified at all. I have a 24' 2500 that was built in Jan. but haven't had a chance to pull my camper yet. And was just wondering if I should worry.

I believe if you have solar and a generator the power that's charging the battery sends power back to the truck and confuses the truck controller so you get the code. I have both on my 38' TH so I got the error message almost immediately when I had power switched on in the RV while hooked up to the truck.

I'm sure someone will be by to be the expert on the matter. BUT the only way the stealership will change out the controller is if you get the code.

Rick_ · May 14

On 3/25/2024 at 10:03 AM, Rick_ said:

I took my truck in last week for the Trailer wiring messages and they replaced the brake controller with the updated version straightaway. There was a code stored, C114, that affirmed the issue I was experiencing.

One thing you can watch is flip the message center to Trailer Brake and watch to see if it the "bar" is grayed out or illuminated when the messages are appearing. Grayed out means the trailer brakes won't apply and illuminated means they will apply.

Went camping this week and no more trailer wiring messages after the update, brakes worked fine, and the solar charger went into “float” mode perfectly after the batteries were fully charged.