Hooked up batteries Backwards
So I got 2 new batteries for my 99 Jayco eagle motorhome, however when installing the camper battery I hooked pos. and neg. backwards. I then Hooked up the engine battery correctly, when I went to turn my key, I immediately turned the key off because there was smoke coming from the hood. I assume that I have blown a relay somewhere. I since am unable to get anything engine related to turn on, I can however still run all camper related power systems plugged in or on battery power. I have checked all fuses in cab and engine compartment, as well as camper fuses and can't find any that are bad. The camper battery has power to the relay and splitter next to the water control box, so I am thinking this is all in the engine. Any suggestions as to what I should check next, are there any fuseable links, has anybody ever done this before. The new engine has less than 1200 miles and cost 6k to replace about a year ago in an emergency repair in Indiana.