cloud dodger

Thanks for the reply Bruce. I don't use the 12V line to exclusively charge the trailer battery. I plug into shore power at home or when I camp to charge the trailer battery. My '24 GMC 3500 Denali DRW truck got a new integrated trailer brake controller from the GMC service bulletin and the part number is 23306694. My understanding is that this controller is what was used on '23 trucks, but it works without problems. I towed my trailer a few days ago after the install for a test drive of 45 minutes and about 20 miles - no issues. So I hope this problem is fixed, but I'm going to keep the diode just in case. I'm still looking for help with how to install the diode. In the picture the 10 gauge black wire under my thumb is the 12V that goes to the 7-way pin. But it connects with three other wires with a twist connector. So how do I install the diode with those other wires all connected together? I have little experience with this kind of electrical issue. Trailer wiring in junction box.HEIC

Hello everyone - first time post. So I've been following this thread as I've been experiencing the brake disconnect issues while towing my 20,000 lb fifth wheel with my '24 GMC Sierra Denali 3500 DRW. I had the service bulletin accomplished on Monday at my local GMC dealership and the brake disconnect problems still occurred. I am going to try the diode fix and ordered a Roadmaster 690 diode. I understand the diode needs to be installed on the 12 volt connector to the 7-way plug which I believe is in the junction box under the kingpin. I have never done this kind of electrical work before so I need some assistance. The attached picture shows the wires in my junction box. I can see the 7 wires that go out to the 7-way plug. Do I find where the two 12 volt wires are connected and install the diode between? Which wire goes to the IN side of the diode & which to the OUT? Appreciate any comments from those of you who have done this fix already. Big D junction box.HEIC