Does anybody know if you can replace the bulbs behind the heater switch dial?

The numbers around the switch on the passenger side seem to be very dim as if a bulb has gone. Everything else is fine. Reformed

Well I have taken the switch pack out to have a look behind and it looks like a sealed unit!! (Easy to get out though).

I removed all the plugs on the rear and have made sure they are all tightly back on, all the switches work as they should so looks like they will either stay dim on the passenger side (I dont fancy buying a new unit just for a bulb!) or keep my fingers crossed it was a loose wire that is on tight again now!

Just got to wait until it gets dark now as it is to light to see if the lights are working behind the numbers. Reformed