My neighbor called me a bit ago, asked if I could come down and help him find the source of his beeping problem. Car is a 2005 Chrysler Pacifica with 122k miles on it. He had the battery disconnected overnight. No matter. There is a constant, high-pitched beeping (think smoke alarm-ish) a half-second pulse every 2 to 2.5 seconds. Sound apparently originates near the top of the center stack, in close proximity to the analog clock.
He tells me his wife was driving the car last night to pick him up at the airport, and as she neared the airport, it started beeping. It has not stopped since.
So what is the cause of the beeping? Anybody familiar with these Franken-Chrysler-Benzes?
I have a hunch or two, but I'm keeping them to myself so as not to bias the replies. 
John Welsh said:
Does it start, drive?
Yup. Starts, drives just fine. I hooked up my OBD code reader and it returned zero codes. Only light on the dash is the ABS light, but he says that's been on for months. The beeping does not stop. Door can be open or closed, car can be running or off, battery can be disconnected overnight. It beeps. Constantly.
Trunk hatch lid not closed tight? Bad sensor thinks it's not closed?
Brake fluid low? Since abs light was already on its an unnoticed change
Air bag module.
If it's in a rusty area, wiring and/or front impact sensors are bad.
Ranger50 said:
Air bag module.
If it's in a rusty area, wiring and/or front impact sensors are bad.
This is the way I was leaning. Not sure about rusty. Car looks pretty rust-free, as in completely. It may be relevant that being parked in the sun has caused the entire passenger side of the rear edge of the dash cover to pop up and separate from the glove box area.
Assuming it is airbag related, why is there nothing on the entire internet about this incessant beeping?
In reply to Ranger50 :
Also, you sound pretty sure. What is the basis for your confidence that it is in fact the airbag module?
In reply to 1988RedT2 :
I have done berkeleyed up enough of my own cars. Air bag modules beep when something is wrong that a bag won't deploy. Especially true on the primary side, ie driver vs passenger. I forgot to say, this could also be the clockspring.
1988RedT2 said:
Assuming it is airbag related, why is there nothing on the entire internet about this incessant beeping?
Only thing to do is fix it or dig into the dash and disconnect the module which will probably take down the can bus and make it inop.
In reply to Ranger50 :
Okay, makes sense. Owner says he restarted the car and it stopped. So, probably something somewhat intermittent, maybe clockspring. I'm headed down there shortly for some home-baked apple pie. 
Does one airbag module control two or more airbags? Or does each bag have it's own module?
Thanks! 
In reply to 1988RedT2 :
One module for whole car.
You likely need a more advanced scan tool to get the codes out of it. Standard OBD won't return codes, you need manufacturer-specific data.
