Electrical issue

[gem2002]

I have a 2002 E825 gem.This year when I brought it out from storage I started to have issues.When the ignition is turned off and the E brake is off the display board flashes all Zero’s or what ever level the batteries are at.If I apply the E brake 04 code comes on the display with the red light on over the wrench.That would be a normal condition if the key was on.When I turn the key on the Gem appears to be normal.I know that this condition is taken charge off the batteries unless I hit the kill switch everytime I turn the key off.I would appreciate ANY advise on this Thank you