Have RV Questions? Ask an RV Mechanic Online.
Hi! My name is ***** ***** I can assist you with this. I may need some additional information from you first in order to give a complete answer.
Start by having the alternator checked. It may not be putting out the correct DC voltage to the isolator. If it does, then you can check the outgoing voltage to the battery(s) and see if that is correct. It should be near 14 VDC and you can use a small digital multimeter to check that. About $20 or so at most hardware stores and easy to use. All follow ups are included in our fee. No time limit.
On the coach battery does the positive and the smaller wire connest to the positive ?
What color is the smaller wire?
Probably a positive lead. Where does it come from or can you tell?