So you have put the battery wiring right, and now the slide works in /out ok?
If so, you are on battery but no converter if on shore power to recharge the battery, so look for the RP fuses on the converter or else on the DC fuse panel next to the converter. Might be say, two 30a fuses. Other sizes and numbers possible.
Please post the model of the converter (as seen on the power centre when you drop/open the panel, so we know where the fuses are.
Digital multimeter has a black and red lead.Red is pos. so with red lead on pos battery post and black lead on neg battery post the display will say, eg 12.56 volts. If you put the blackl lead on the pos post and the red on the neg post, it will say, - 12.56 volts.
That is handy for trouble-shooting so you can tell which is a positive wire in a pair you are not sure which is which.