Demister/Aircon LEDs not working?

[Ozzy]

I was changing the heater control bulbs a while back and had the fascia on and off a few times. Since then, the LEDs for the aircon and demister buttons are no longer lighting up when pressed but still work fine.

Any ideas why? Is there a fuse for this or can the bulbs be changed? I couldnt see any with the fascia off.