Had the same probem on my Soparanos safe. The wiring harness is the culprit. Routed poorly and attached poorly. We added Sugru compound at the contact point on the safe to keep the wires from flexing at the solder joint. Sugru is a soft playdoo like plastic that you mold over the wires and contact point. You let it cure for 24 hours before you play again. Cured our safe problems. Sugru is available at the Sugru website.
Good luck,
Mike