Steve, is this the controller your talking about. I think these are the battery equalizers. Four of them and they all test good.


If there is another Vanner controller, a better description and location would help. My batteries all tested good after being disconnected overnight. A call to Prevost service also mentioned the Vanner controller and said no problem driving the coach if the dash voltmeter stayed below 29 volts.
Still searching for the problem, but so far everything checks out ok.