Trailer over drawing on tow vehicle?
In a strange situation, hoping someone can offer some insight. We previously towed a tent trailer with a 4 prong wiring harness, swapped for a 7 prong (installed at a reputable company) to tow the new hard side. Never had any issues towing the tent trailer, now AFTER we finish towing the new unit and have DISCONNECTED electrical the check engine light comes on when the vehicle is restarted. Mechanic ran the code and said it’s throwing a code due to low voltage in the battery. The trailer batteries are full, confirmed on panel in trailer and are connected to mounted 200W solar on the roof which would keep them topped up. I included a picture of the trailer batteries in the event we have something wired incorrectly.
We will be returning to the electrical installer Monday when they open to see if there are any issues there.
It may also just be that we need a new car battery but haven’t had any issues with it until towing this weekend.
Any insight is appreciated! Out of my depth on this one.