Not sure, but if you can pull the dash bezel off, you should be able to get the temp control unit out far enough to see the backside of the switch or maybe even the bulb holder. On the pushbutton switches in the dash the bulb holder is about 1/4" diameter plastic, brown, black or green with a cross recessed in it. If it has this, turn it about 1/4 turn CCW to remove. I suppose it might also be an LED. If that's the case, you'll have to blaze a new trail.

Keep us posted.