When opening or closing the driver door the interior lights do not work about 90% of the time. They do light up when the car is unlocked using the fob, but no other time. Also, the "idiot" beep that the lights are on, turn signal is on, etc when I get out of the car does not sound. It looks like the car does not know if the driver door is open. Where is the sensor that tells the car the door is open?

Somewhere in the wiring they are grounding out and I suspect the keyless entry because it's the interior lights and locks at the same time when you use the keypad it lights up and the interior lights come on and the door locks open and close using it so open the drivers door or if you see that those key pad buttons have holes in them from using a key to punch in the numbers there's water inside and it's shorting out the wires

Courtesy Lights
The courtesy lights come on under the following conditions:
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Any door is opened.

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The interior lamp switch is in the ON position.

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The keyless entry transmitter unlocks the doors (illuminated entry).

When the key is removed from the ignition switch with all of the doors closed, the courtesy lights light for approximately 25 seconds before fading out.
Battery positive voltage (B+) is applied at all times through the IP fuse block CTSY LP/PWR MIR fuse 6A via CKT 640 (ORN) through the body control module (MALL) to the courtesy lights via CKT 1732 (ORN). The MALL provides a ground through CKT 156 (WHT) for the courtesy lights under the following conditions:
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The MALL receives an input from a door being opened.

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The MALL receives an input from the interior lamp being turned ON.

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The MALL receives an input from the doors being unlocked using the keyless entry transmitter.

The courtesy lamps then light.
When the courtesy lights are activated by opening and closing a door, the courtesy lights will remain on for approximately 25 seconds before fading out after all of the doors are closed. If the ignition switch is turned to START or RUN within the 25 seconds, the lights immediately begin to fade out. If a door is left open, the MALL removes battery positive voltage (B+) to the courtesy lights after 10 minutes. When the courtesy lights are activated by the interior lamp switch, the lights remain on as long as the interior lamp switch is in the ON position. When the courtesy lights are activated by unlocking the doors using the keyless entry transmitter, the lights remain on for approximately 40 seconds. If the doors are locked using the keyless entry transmitter within the 40 seconds, the lights immediately begin to fade out.
Body Control Module (MALL) Diagnostic Mode
For a detailed explanation of the MALL module diagnostic mode, refer to Body Control Module Cell 51.
What interior light ? Dome , courtesy lights etc....They don't work with switch, keyless entry , door opening ?
What

Same for both doors? If not, I'd check the switch(s) on the drivers door (may be more than one), or may be just one that has multiple contacts and the ones for the lights may be faulty.

Hi, viewer. The interior light is powered and controlled by the body control module or BCM. However, there is an on/off button beside the main headlight switch that overrides the interior lighting function. If this button is off, interior lights will not come on regardless of any door being closed or opened.

If this button is on, interior lights will come on whenever a door is opened. If you close all doors, and if the driver door is the last to be closed, the interior lights will stay on for about 30 sec and then the lights goes off automatically. In case you left any door opened too long, the BCM has an internal timer that will shut off the interior lights automatically when it detects that a door is still opened and the allowable time has elapsed. The BCM is programmed this way to protect the battery circuit and functions. : )

counds like dirty contacts in the door frame

this problem i have repaired many times.. it is normally a broken wire in the flexible rubber tube between the door and the doorjamb from years of flexing back and forth when you open and close the door.. i hope that helps

the best lube to use for these latch assembleys is PB BLASTER available at your local parts store. spray each latch really good one at a time, then open and close door 10 to 15 times. trust me PB BLASTER takes care of this 90% of the time

theres a little switch on the body of the car that turns tat interior light on and off yours could be faulty

hey there
this sounds like a common problem for the Taurus
at each door there is a button that lets the driver know there is a door open and also dose the interior light(s)
one if these are broken
they are easy to fix and cheep to do as the part can be a used one from the wrecking yards
all you need to do is take the switch out and unplug it
do one at a time checking each time to see which switch it playing up
when you have found it just get the new part and install it
WHEN THE SWITCH IS OUT MAKE SHAW THE WIRES DONT TOUCH AS THIS COULD CAUSE A SHORT IN YOUR ELECTRICAL SYSTEM I WOULD USE MASKING TAPE TO HOLD AND PROTECT THIS FROM HAPPENING
if you don't really want to use the lights and warning light dont connect the wires and put the old switch back in
YOU MUSH NOT LEAVE THE SWITCH OUT AE IT WILL CAUSE CURROSION AND ALSO CAN LET WATER IN PLACES IT IS NOT MENT TO BE
let me know how you go
ricko