Lack of power to van.

Just purchased a 2013 Kia Sorento and had the dealer fit the towbar. On our first outing the fridge didnt want to work and the ATC decided it didnt want to work properly (had a green light then no light then avred light). I went to the caravan dealer as I thought it may have been the van as it was our first use of our new caravan. The dealer hitched up to another van (same make and model) and the same thing happened. The dealer said that it looks like the Kia dealer didnt wire it up correctly and that this is a common problem. Has anyone else had this problem or is it just me.