Ford 7.3L Power Stroke (1999-2003) :: 2002 F250 - Panic Alarm Horn Sounding / Dome Light On

I own the above described vehicle; I'm at about 196k and I'm the original owner. It's a quad cab, 2002 7.3L with power everything. I believe it's the XLT package (it's not in front of me... I'm at work. CONFIRMED... XLT package).

Currently, it's the workhorse and back-up for the family, not my primary driver - luckily. I've had failure if the automatic door lock on the rear pass. door, and a sticky lock on the rear driver's side lock - they've both been in this state for at least the last four years, no problems beyond the hassle of manual manipulation of the door lock from the inside - otherwise no electrical issues really to speak of.

Three weeks ago, we went to the snow. I rarely use the 4x4, but found that I had to use it that day to get out of some mud - it worked fine, no issues. In addition, I also used the cruise control... something I do rarely, but have not had any issue with it either.

In exiting the area some hours later at the end of our day, I noted two things... the "door ajar" dash light was illuminated and did not shut off through the drive home, and the dome light remained on until the battery saver shutdown shut it down... quite some time (where normally a key in the column turned past the insertion would shut it off).

When I drove home I used the cruise control, as mentioned, and it worked fine.

In exiting the vehicle while at home, as soon as the door was opened the horn started blaring panic alarm style - honk, honk, honk, honk... - and when the batteries are attached, there is nothing that stops the honking, except the battery saver timeout. BTW... no key in the ignition.

I don't use the FOBs... the batteries were dead anyhow (and I moved the FOBs out of range of the vehicle).

Attempted fixes:

- Lubing the lock/WD-40, then shutting/opening the doors (no luck/no change).

- Pulling door panels, removing locking mechanism, removing door ajar switches (I don't know what they're called), manually manipulating the piston AND checking each with a multimeter. (NOTE: One "seemed" not to work properly, so I purchased one from dealer and placed it back... still, no luck resolving the issues overall).

-Checked the wiring looms supplying all four doors - no broken wires noted.

- Replaced the two vehicle batteries.

I'm at a loss and I'm hitting up this forum before I move forward...

I've read that there are issues with the VSM for this year's model, but I'm hesitant to purchase the module without further feedback from a tech. I've read some general posts about alarm systems (doesn't apply to me) and horn issues (but those were horn constantly blaring... not the intermittent horn blasts of a "panic alarm sounding."

I've heard that the GEM and clockspring could be an issue, but I have to look more closely at the associated problems (like recheck to see if the cruise works... door windows go up/down like some threads have mentioned...). I have also read that the door ajar sensor switches attached to the automatic locks could be culprit, as they may "work" when pulled out, but not work when they're installed in the vehicle.

Ultimately, what the cause to the panic horn beeping, dome light and door ajar instrument indicator being on.