I have a 2007 1st gen Mazda3 hatchback. I'm the original owner and have had it since new. Recently I have been having an intermittent problem with power cutting out to the head unit (radio, clock, fuel economy info and outside temp.), and the interior lights wont turn on. It also thinks a door is open but the interior lights won't work so it doesn't kill my battery, and when I turn the car off the trip meter gets reset.

All four things (head unit, open door warning, interior lights and trip meter) are connected somehow and all occur at the same time. When it acts up while it is parked, it thinks that a door is opened and the alarm goes off which is super fun in the middle of the night!

I took it to a shop to get looked at but the problem is intermittent so they were unable to diagnose the problem as there were no symptoms at the time they were looking at it.

I am currently just leaving it parked unlocked so the alarm wont go off.