Just went through something like this with my HVAC control panel.
I installed a new stereo a couple of years ago so while I was so close the the lamps in the heater control, I checked them. They were black and clearly removeable so I checked with Dodge - they said not serviceable but you can buy a whole new control.
I found replacement bulbs on Rockauto but they fit loosely. So loose that they melted and got intermittant. I finally just soldered them in.
So you might check Rockauto for parts. Just make sure the fit tightly or just solder them in.
