After my heater/AC controls started going dark, I went to my local Ford dealership to find replacement bulbs, but the parts person was not able to find a part number for the EATC (Automatic Temperature Control) bulbs I needed for my 1999 Mercury Villager. After measuring the diameter of the bulbs (3 mm, or 1/8"), I was able to find something that would work. The plastic bulb socket twists out and then the bulb can be removed from the socket by unwrapping the two wires. Radio Shack sells a package of 2 T1 bulbs for $2.00. The bulbs are about 1 mm or so longer than the originals, and they burn a bit brighter, but they still work. The part number is 272-1092 (or #7219 Micro Lamp, 12 Volts 60ma Wire terminal base). I found other sources on the internet for these bulbs, and some with sockets.