This is a common fault.. I had it with mine !!
The backlight is a strip of white LEDS not a bulb.
This is incorporated into the "click together" clmate panel assembly..
No offence webby but isn't it about time Renault made a simple fix for this unit instead of expecting customers to replace the bloody thing whole thing..
The unit itself can be dismantled down to board level with ease, surely a replacement board or LED array would be sufficient..
If anyone else has this fault with their Renault Climate Control Panel please mention it here. I would like to see if we can get something of to RUK with a lot of following.