You apparently have internet access so look for the name of the jacks on the RV and then download the manual and troubleshooting guide from them. The 6V batteries were connected in series to give 12V. If you can't get Pep Boys to straighten up the battery mixup you can use 2 12V in parallel for the right voltage. If they were hooked up in series you were putting 24V to the accessories. For parallel battery hookup you put both positives to the positive input on the coach and the 2 negatives to the negative side of the coach wiring. Series has positive of first battery to negative of second and then positive of that battery goes to the positive side of MH. Reverse applies to the negative input side.