Possible Battery Isolator Problem 1996 Roadtrek Please Help

[a1parrothead]

I went out this morning and my Roadtrek would not start. Both the engine battery and the coach deep cycle battery was almost dead. I could see that the red light on the control panel was on, indicating that I had left the battery switch on.

I have an Intellitech brand battery Isolator switch in this, which has 2 fuses.

So, why did my engine starting battery go dead? I thought that the isolator was supposed to prevent that?

Here's more about how its acting: When I have the ENGINE/starting battery connected (vehicle motor turned off), I get 12V reading back at the coach deep cycle battery cables (obviously the cables have been disconnected from the deep cycle). I should not be getting any bleed through from my engine battery should I? This seems to indicate that my engine battery can be drained by my deep cycle battery.

But…… it seems that the 12v will not travel the other direction, because: If I disconnect my engine starting battery under the hood, and leave my deep cycle connected, I get no power to the battery cables under the hood. So it appears that power from my deep cycle cannot travel to my engine starting battery.

OR….. Is it the red box in my engine compartment under my battery that says "Powerline Solid State Battery Isolator"? It has 3 connections, a connection for the main battery, auxiliary battery, and alternator.

Is it this battery isolator? Any help would be appreciated.

Jeff

[dreed]

I suppose you could disconnect the rear battery connection at the isolator for a couple of days and see if it drains the front battery. If it doesn't then you start to troubleshoot the house battery. You would check for excessive drains and also battery condition.
Dave 04 Excel TD

[Mandalay_Parr]

It's possible that you are getting false readings IF you have an electronic solid state isolator AND you are measuring an open circuit with a high impedance meter. ie, leakage current.