e36 94' 316ise, dash keeps cutting out

[darkz]

hiya guys (and gals) wondering if ya can shed some light on a problem im havin.. have just recently picked up an 316, and when im driving along, for no apparant reason the dash just cuts out.. as in the speedo, tachometer, coolant temp and fuel level temp, and all thewarning lights, tripometer etc.. the backlight stays on, just anything that is meant to be giving a readout dies. this can last for just a few seconds or sometimes 10 min at a time. then it'llm suddenly just pop back on again... ive tried seeing if its a loose connection , there doesnt seem to be any local cause for it to go, when it goes i can smack the dash and all over the dash both passenger and driver side, doesnt seem to make it come back on.it'll just pop back on again.. I'v had a look at a basic wiring diagram for the dash and it seems most parts of the dash use the same earth point, but im damned if i can find it. Any idea's peepz? was wondering if it could also be a controller module or the ecu playing up, or more likely a loose/broken wire
thnx
darkz