7 pin upgrade to boat trailer
My van is 7 pin. The trailer is 4 pin. I had a shaky 7-4 adapter. I wanted to access the 12VDC trailer power to charge devices in the storage box, like the VHF and the outboard battery, while towing. I also wanted a 120VAC pass through for shore power.
I mounted a waterproof junction box on the storage box.Coming out, it has a 7 pin lead to connect to the van, a 4 pin lead to connect the trailer lights, and a 120VAC inlet. Inside the junction box there is a terminal strip. That breaks out the trailer light wiring and the 12VDC.
There are 2- 12VDC fused cigaret lighter plugs facing into the storage box as well as a 120VAC outlet. The 120VAC powers a 300w cabin heater that keeps the gear dry while stored. At the campsite I can charge the electric outboard battery off of shore power. Now I can keep the lid closed and locked.
'07 GMC 2500 6.0