I disconnected my battery to change my spark plugs today. With everything reconnected, the engine runs fine. Afterwards, the car produces a clicking noise at about 1 Hz for periods of several seconds. The clicking noise is coordinated with the radio backlight flashing and the turn signals blinking too. I'm worried this will drain the battery.
What did I mess up?
I tried manipulating all driver-side controls and buttons but didn't find anything that would stop the ticking.
Here's a video, if it helps: https://www.youtube.com/watch?v=LLxIgL4OBXQ
1998 Subaru Outback (2.5L).