Funny you guys mention this. I just got my 03 4Runner back from the dealer after fixing this "little" problem. I thought it was a lightbulb issue and so did the service agent at the dealer who told me my car would be ready the next day. It turned out that the problem was with an internal switch not making contact and they had to order a new temp controller. I got my car back a week later. The replacement part cost almost $900. Luckily I had the extended warranty and it was all covered, including the use of a loaner car. I really hope this does not happen again.