97 Sun Voyager Coach battery connections

[kw4]

I recently acquired a 97 Sun Voyager 34 ft and when installing new coach batteries, I ran into connection issues. At the back of the compartment, there are two entrances for cables. The cable on the left is the appears to be the negative side and the bigger of 2 cables on the right side is positive. There is also a smaller cable on the right that is connected to a white block on the right side of the compartment. The cable leading from this block is more than long enough to reach the negative post. Could it actually be a positive cable? I don't want to risk causing a short.

P.S.
I have no power to the slide pump motor. Thanks for the help.

[kw4]

It was positive for the slide motor. On to other electrical connection issues in a unit with no documentation.