I have just responded to a similar comment on this page.
your problem seems to be the same as mine.
the bulbs which illuminate your dash take their power from a printed curcuit board which can easily be torn or damaged and another fault is that if the bulbs do not fit tight enough they will come on and go off at will!!
i have made a temporary fix by securing them in with insulation tape however to fully resolve the issue i will have to either by a new printed curcuit or new bulb holders.
my advice is to take them out put the inginition on and hold them in if they come on it is a bad connection.
garry
November 2008