Look in the interior modifications section of "Tutorials & FAQs", this will explain how to gain access and replace these three bulbs. The middle one does the heated rear window switch (there is no separate bulb in the switch itself).

Hope this helps.

Hey guys, i recently put some blue leds in my car behind the MFD speedo etc etc. I was left with one and at the time i thourght nothing of it. I now know that your meant to have 3 leds in the heater control section. Could anyone write me a really easy tutorial for how to get to the led behind the middle heater switch (The one with the yellow filter on showing teh heated windscreen), because at the time i couldn't seem to get to it. Thank you very much:)