Multiple failures

My check engine light came on with a 0601 ECM code. I know that I need a new ECM its the new stuff that has me perplexed. Now today the windshield wipers, stereo, heater blower, door locks, power windows, turn signals and rear window defrost all stopped working. The engine worked, the headlights worked and the inside dome light worked fine. Then I turned the engine off. Just as I turned the key off they started working again. Then I went to get gas and when I started the engine the same thing happened again. Oh and prior to all this the radio lights flickered some times and the dome light wont stay on when in use. Help