Opening a door is only an input to the computer, the computer then decides how to act on the output. In the case of police interceptors with "Dark Car" mode enabled, the response is to ignore the open door signal and not turn on the domelight. Turning on the switch to your headlights or parking lamps is likewise just a input to the computer.

Note that 1995 and later crown vics & grand marquis do not use a conventional standalone turn signal flasher module. But this does not deter numerous aftermarket parts stores and backyard mechanics from insisting that they do. I find it humorous everytime I hear of an uninformed backyard mechanic purchasing a can flasher for $5.99 and then tearing apart half their vehicle's dashboard looking for the old one, but the vehicle owner is typically very frustrated and mutters many curse words in the process of looking for the nonexistent part. Some have also observed that the fuseblock on 95'-00' crownvics has a properly shaped place where a can flasher will fit, but there are no electrical contacts in the socket. This is because the ATC fuseblock is a common part shared among numerous vehicles and ford saw no need to redesign it until the crown vic went with mini-fuses in the 2001 model year.

Below are a couple pictures of the circuit boards inside the lighting control module case. The smaller relay is for the turn signals, the other larger ones are for the low beam headlights, high beam headlights, parking lamps and demand lighting output. The round device labelled "TMX-06 95'G" is the seatbelt/headlight/airbag audible warning buzzer. Besides the controlling the lighting, the LCM also controls rear window defroster, but the relay for defroster is located in the engine bay and not on the LCM circuit boards like the rest of the relays.

Physically Locating the LCM:

It should be noted that the pictures above show the lighting control module with it's black metal case removed. The lcm may appear smaller than the pictures above portray because the the white ribbon cable between the two circuit boards is flexible and the two circuit boards lay one on top of each other inside the case, not side by side like pictured above.

Also note that the lcm circuit boards have a "conformal coating" applied to them to inhibit corrosion of the metal parts underneath. This makes the circuit boards feel somewhat "gooey" if you touch them with your fingers and also creates a "white out" effect when taking a picture of them with a camera.

The lcm is mounted in the same location in all 1995 and later crown vics. It's under the dash, above the gas pedal in between the climate controls and steering column. If you're having trouble locating it, engage the hazard flashers and listen to where the source of the clicking sound is coming from. You can also place your keys in the ignition and open the drivers door and track down the module by listening to where the warning buzzer tone is coming from.

If you need a visual reference, pictures of a mercury grand marquis dashboard removed from the car with the lcm still attached are avaliable by clicking here.

Year to Year compatibility:

Some have asked about LCM compatibility between model years, below is a chart listing the lighting control processors used in crown victorias and grand marquis.

• 1992-1994 crownvics do not use an lcm. The headlight switch carries the full electrical load of the headlight bulbs and parking lamps.
  
• 1995-1997 lcm's have one additional electrical connector on them for the highbeam circuit that the 1998 and later models do not. Additionally, 1997 and prior vics have a 4 headlight bulb system, 1998 and later ones have a 2 headlight bulb system.
• 2000 was the first year for the "belt minder" system that sounds the warning buzzer every few minutes until the driver buckles their seatbelt, it was also the first year for the all red police taillights with two bulbs fewer than its civilian counterpart. The 2000 electrical connector pinouts are identical to the 1998 and 1999 connectors.
• 2001 and 2002 crownvics use the same electrical connectors as previous years but the function of a few of the pins has changed a little due to the addition of airbag restraints control module.
• 2003 and later vehicle use connectors that have physically different dimensions than earlier vehicles did.
• Police interceptors use the same lcm's as the civilian crownvics & grandmarqs.
  
• Do note that the 1995-2005 crownvic/grandmarq lcm's will NOT fit in the lincoln towncar. However starting in the 2006 model year, lincoln towncars started using the same lcm as the ford crown victoria.
• An interesting microsoft excel document listing the engineering part numbers for all the 2003-2005 lcms and what the differences are between them is avaliable by clicking here.
• A document showing the configurable options inside a 2008 lcm is avaliable by clicking here.
• TSB 02-9-7 is avaliable here.
  
• The part numbers listed in the "Legacy Part Numbers" column have been discontinued. When you order a new lcm, you're going to recieve the one listed in the "Part Number" column unless your particular ford dealer has some old stock sitting on their parts shelves.