GM brake controller failure update
I’ve learned a few things on what GM knows about this problem, but there’s no solution just yet.
It’s an interesting can ‘o worms
Yesterday I posed my theory on why the onboard trailer controller in 2024 GMC 2500 and 3500 trucks will randomly disconnect your trailer brakes. GM has known about this dangerous problem since late June, but doesn’t seem to know how to fix it, and they just recommend you shut off the RV solar panels to prevent the back-feed voltage which can disconnect your trailer brakes.
Here’s the Bulletin Info
But GM dealerships don’t seem to know about it…
If you have this problem, please show your GM dealership this info and don’t let them hack up your RV’s 7-way plug. But do learn how to disconnect your solar panels from your RV battery while towing, which is apparently the trigger.
Here’s a copy of the document from a reader
When I know more from GM I’ll post additional information. In the meantime please don’t tow your trailer without the electric brakes working. Try the solar panel disconnect and see if that works temporarily. And please let me know anything you hear from you GM dealership.
Let’s play safe out there - Mike
It’s a 2-way communication path over the 7-way plug. The truck brake controller also monitors current to know if your turn-signal bulbs are working, etc…
Well, I’ve personally received a few dozen emails about this over the last several months, so it must be a problem. And many (most) new RVs are offering solar panels as an option. I hope GM pays attention and issues a real fix, since it will only get worse as more trailers have solar panels and lithium batteries.