Found these answers on the Fiat forum. hope they help -
'Behind the glovebox,push metal pins in on side of glovebox to lower then pull out fuse cover.'
'it seems that there is a general fault with the radio and clock in these vans.
mine also doesn't work because there does not seem to be a permanent live to either the clock or the radio!!! my mate has a peugeot expert (x reg) and his has the same fault!
also the interior light only works when the ignition is turned on, so if it is not working check the bulb!!'