Change Lights behind speedo clock and Aircon

[F1r3ball]

Hi guys,

I just tried to change the bulbs from the clock of the instrumental cluster because its dark at night so I think they just died. the problem that I have is this bulb holder.
I want to replace it with blue bulbs and thought its a simple T5 but ...the oldstyle
Does someone of you guys here have an idea how to do it or is there a chance to buy allready fitted bulbs ?

The size is 10mm and looks like that :Picture from the holder

Maybe you guys can help me with that problem.