I have a 2007 Honda Odyssey (44k miles). Last night my son unlocked the driver's door with the key rather than the fob/remote. He then opened the passenger door with the driver's door UNLOCK switch. We both got in the car and fastened our seat belts, when I noticed the flashing red light on the dash. Before I could comment that the light should not be on, he started the car. Immedietly, the horn started honking and flashers started flashing. I tried to reset the alarm with the key fob - no luck. The electrical UNLOCK switches also did nothing (did not even lock/unlock the doors!). I ended up pulling the ground wire from the battery. I hoped to reset whatever had happened. This morning, as soon as I connected the battery, the horn started sounding.
So, does anyone have a clue where I should start troubleshooting? It seems the Alarm logic is off as well. Shouldn't the alarm have started sounding when the door was opened? Certainly not when the ignition is energized!
Any help is greatly appreciated!