I just noticed the other day that my indicator light for 4-wheel drive knob wasn't working. Has anyone else had this problem, is this major or is it a case of a burnt out light bulb?

Yes, it happened to mine as well a while ago.

Turns out that I no longer had 4 wheel drive!

You are going to need a new switch....that's the problem, not a burnt out light.

Is this a costly repair?

Has anyone changed the 4-wheel selector switch themselves? If so, how do you get at it in dash, from underneath?

Thanks!
Art