Before you spend more money, check the settings for things that make a working camera look dead: operating hours set to daytime or nighttime only, a time-lapse schedule, a long trigger delay, or setup and test mode left switched on.
I lost a fortnight to operating hours I had set in summer and forgotten. If you are unsure, reset to defaults and build the configuration back up. Then the case seal and gasket, and the firmware, in that order.