Wiring for house battery in GREYHAWK 26y

[Rueckert]

Ok...I have a situation needing help. I have a Jayco Greyhawk 26Y...I added a couple of batteries into the next compartment...know I did it all right...had dealer add a battery meter inside to read levels etc. Then I had an accident and RV was repaired...took out of storage and cheaper deep cycle batteries had died...so I removed all...but as I took them out...I saw that nothing was hooked up to the negative terminal of the house battery except my jumper....and 3 leads were hooked to positive of house battery...one colored red and 2 black. I wish they were color coordinated for where to go...but I am freaked out now that they are wrong...that one of those black wires should be on negative? How do I sort this out? Help please