So, figured I'd share with you my experiences in upgrading my interior lamps to LED.
The stock incandescent bulbs just weren't cutting it for me, I wanted a little more light, and perhaps a reduction in current draw (haven't compared that yet).
So, off to Ebay I went, shopping for 39mm festoon LED bulbs from China (for ~$1/each shipped to my door). At that price, I figured I'd try out a few different styles to see what worked the best.
If you want to find some for yourself, just put "39mm festoon" in the search box, and you'll get a bunch of hits. If you want to find something like what I eventually went with, search for "39mm festoon 5050" to get the style I liked.
Lets start with a BIG NOTE about POLARITY! LED bulbs (at least most of the ones you find on Ebay), ARE polarity sensitive. So, when you stuff them in the socket and they don't light up, make a note of which way you have them installed, and pop them back out and reverse the connections. A dot of ink from a felt marker is handy here.
Lets move on to what doesn't work.
These are (apparently) 2W 39mm 2 LED Festoon bulbs:
Garbage. 3 of the 5 I ordered failed out of the box (didn't light up, or were intermittent with temperature). They are also much dimmer than the stock bulbs.
These are 39mm 3 LED Festoon bulbs:
More garbage. Still dimmer than the stock bulbs.
These are the ones I finally found that I was happy with. They are 39mm 8 LED 5050 Festoon bulbs:
The 5050 is the size of the individual LED elements. They are brighter than the stock incandescent bulbs, and have a nice cool white color temperature.
I see today that there is also a 9 LED 5050 version as well, that would be a little brighter.
I tried ordering some of these to try:
But, they never showed up. I suspect they would be a little dimmer than the 5050 ones, as the LED's on these are a little smaller. But, I could be wrong. Maybe I'll try them one day.
A couple of other notes...
The LED's are directional, so when you use them in the fixtures, you may need to tweak the direction so they blast their light through the lens where you want them (I didn't really have an issue with this).
The sockets in the fixtures are pretty tight on space (the front ones for sure). If you pick something with too big of a PC board of LED's, it may not fit. The stock bulbs are a pain to get out of the front map lights, and the LED's are even tougher to get in... but it is possible. A little hook tool might make the job easier.
Change the bulbs with the DOORS CLOSED and the interior lamps OFF. One of the connections in there is LIVE, and you WILL blow the fuse if you ground it out while poking around and fighting with the bulbs (ask me how I know).
Overall, I am happy with the way the bulbs I bought... makes the interior crisp and bright, instead of the dull almost yellow light from the incandescents.
You may even be able to find yourself some other-than-white colors, if you want say RED map lights up front for better night vision, or something.