So, this is what happened yesterday ~3pm, ~50 degree (F), after an uneventful 30 minutes of city driving. The car is '96 855t, auto. Had taken the car in for the heated seat recall 5 days ago, and driven everyday since without any problem.

Yesterday's scoop, chronologically :

- Stopped the car in the driveway, took the key out as usual, went inside the house for 10 min or so.
- Came back out and the car wouldn't start. All dash indicators come on as usual, radio works, but engine doesn't turn over. No go after several tries.
- My son, against my plea, opens the driver's side door from outside, and the alarm starts going off. My son thinks he broke the car. Took the key out, tried both buttons on the remote, which didn't do a thing. Tied turning the key in the ignition - alarm continues to annoy my neighbors. My 1yo daughter in the back thinks it's funny and starts giggling.
- Alarm turns off by itself (~1 min?? not sure)
- Turn the key again, alarm resumes (doors had been unlocked up until this point) and my daughter now cries.
- Got out, and locked/unlocked the driver's side door with the key, which stopped the alarm finally
- Got back in and turn the key - engine started!

Can't remember when, but at one point, both turn indicators on the dash were blinking very fast, with audible clicks, but much faster than when you press the hazard switch (it wasn't turned on).

What bothered me is, until my son opened the door to set off the alarm, I couldn't figure out how to start the car (jiggling the gear shift didn't work). When the alarm went off, all my thoughts were to figure out how to turn that off, 'cause I was getting embarrassed. Once the alarm got taken care of, the car started fine. So... had my son not opened the door, I think I would've been just stuck till.... ?? I ruled out the infamous lawn mower syndrome, 'cause I didn't move it a short distance.

The car had been running almost flawlessly till yesterday for ~1 yr since the purchase. I say almost 'cause my wife once couldn't start the car on a very, very cold day. It started either on its own, or by jiggling the gear shift.

Any thoughts or similar experience?

I dont think the alarm was activated by the passenger door opening.. that was just timing. The alarm gets activated by the remote. If there is entry to the vehicle without using the remote such as windows down and pulling up the knob or not doing the Keylock sequence to deactivate.
The alarm sounds once someone attempts to start the vehicle. I presume key or no key (hotwire)

Most likely what happened was you locked the car with the remote and possible someone else from your household made entry to the vehicle without the remote. Once you went back thats were you had your problems.

Once last year I had a similar experience. I was was leaving work. I open the car door and insert the key into the ignition. Nothing. After reseting the alarm all was well. I think I accidently activated security feature which happens when a car is entered without the key. I think I simply selected the right combination of door lock and remote key functions for this to happen. Never has happened since.

Bird.