Climate controls show nothing and so cant put on heater or fans

hi all
hope you can help me i have a P38 1997 diesel and the heater shows nothing in the display
the back lights come on with the headlamps but not digits are being displayed and therefore i cant put on the heater or the fan or anything from that console
this has started to happen every so often and normally when i drive for about 15 mins ill hear a click(like a relay) coming from the engine on the drivers side and then it will start working again?
ive checked the relays abit by giving them a tap but dont know if its them and if so which?
also in the past i noticed when id press the PROG button the headlights would dim but dunno if this is related
any help would be great

thanks
gorgeee

Under the bonnet there is a box with fuses and relays in it, on the left as you open the bonnet. If you leave the car on the drive for fifteen mins with the engine running does the relay click then ( you may have to take the lid off ) and if it does can you tell which one it is ?

Cheers, Nick.

yeah will try that anyone know which relay it could be if it is the relay
thanks

tried all the relays and its still not working this time it seems to still be off more then 15 minutes
i have tried wobbling all the wires but no joy
does anyone know of any other relays?or something like that
even the cigar lighter which is on that circuit doesnt work and have tried the fuses

does the clock work?
could it be the becm coz the cigar lighter, headlights, hvac and clock all go thro it?

hi just checked and the clock does work and so does the headlights,i looked in the book and everything on that fuse doesnt work?