We all know our friends at Toyota "missed an opportunity" by not lighting the window and lock controls in the door panels. I followed a 2009 thread by @loner and appreciate that info, but the pic links are dead so I decided to do a step-by-step write up. This mod is pretty easy and really makes a difference in the dark, be it nighttime, parking deck, tunnels, etc. As with all write-ups, this is for info only and you are responsible for safely accomplishing any work on your vehicle.

You will need the following for each door you wish to light:
- An LED bulb designed for a 12V system - I used this orange one from Radio Shack to match the OEM dash illumination.
- Drill & appropriately sized bit (9/32 for the Radio Shack LED linked above)
- Quick disconnects (technically not required but a must for facilitating future door panel removal). As seen in the pics, I used a different type but if doing it over, I would use these as they’re less expensive and more similar to the OEM plugs.
- Method to tap power (I used a red Scotchlok, the kind that folds over the wire and forms a female connection to plug into.)
- Method to ground the black wire (I crimped a ring onto it but whatever works)

Steps:
1. Remove the door panel. (Thanks, @SamNavy )

2. Drill an appropriately sized hole. This is obviously after the mod was done but shows where the mounting hole goes.



3. (Optional) Test the LED to be sure it works. If it doesn't, you'll be glad you discovered it now. (A quick & simple test is to touch the red and black wires to the + & - terminals of a 9V battery. It won't light all the way but you'll know it works.)

4. Install & secure the LED. This is probably the toughest part of the job b/c of the tight quarters. The Radio Shack bulbs have a threaded base and a nut, but it’s really hard to turn the nut to get it tightened down. It’s been a while so I can’t recall whether I gave up and just glued it in, but in any case, it doesn’t have to look perfect since no one will see it. As long as the LED is secure, you’re good.

5. Splice in one half of the quick disconnect to the wires from the LED bulb, red to red and black to black. I soldered the connections and used heat-shrink tubing over each one.

6. Tap the power.

a) Crimp a male blade-type connector onto the red wire from the other half of the quick disconnect.

b) Verify ignition is off. (You may also wish to disconnect your battery, though I didn't.) For the driver's side door, the correct wire is in the large bundle that goes to the door controls. It's the black one 4th from the left on the top row in this pic. Trace it carefully back from the plug b/c there's more than one black one IIRC. The one you want is a little thicker.



Be sure to use the black one since it has switched power. This means the LED will be on whenever the ignition is turned on, but it’s not bright enough to be seen during the day and will do no harm being on. (Do not use the red wire next to the black one; it has constant power so it will likely drain your battery.)

Attach the Scotchlok to the black wire as shown here then plug the male connector in. You may have to cut away part of the insulation on the male connector.



7. Crimp a ring onto the ground wire of the quick disconnect and attach to a known ground. I used this 10mm bolt next to the plastic-covered hole. YMMV, but this bolt was very tough to get started on my truck. A breaker bar may be useful.



8. Connect the two halves of the quick disconnect plug, turn on the ignition, and verify the LED lights up.

9. Reassemble the door and enjoy the knowledge that you will never again have to fumble in the dark for those window and lock buttons.



(This is more yellowish than it really looks but you get the idea.)

To find the right power wire in other doors, use a circuit tester like this one from Harbor Freight.

1. Unplug the wire bundle to the door controls.
2. Attach the tester's black wire to a ground (metal body or chassis bolts are usually good).
3. With the ignition off, touch the tester's metal tip to the metal contacts in the face of the plug. If there's a red wire, try it first. When the bulb in the tester lights, you've found a constant power wire (and know the tester is working). You can eliminate this wire from consideration (unless you want constant power for whatever reason, in that case you're done).
4. Repeat step 3 with the ignition on, ignoring any constant power sources. When the tester lights, you have found a switched power source. That's the one you want for this mod.

That's it. Feel free to ask any questions or make suggestions to improve the process based on your own experience.