Hi,
Exactly the same problem on a friends Mog was elusive to fix.
However it turned out( after a dealer looking for three weeks) to be a part Morgan call the Indicator Module. It is listed in Ian Bretts alternative parts list on MTWC website. Available from dealers to order and a bugger to fit. It has been responsible for many similar problems, I now carry one as a spare !
rgds
Ian


Ian
Morgan Family 1929 ( KTW 1100cc )
Morgan S/S 1934
Morgan F4
M3W 2012
Morgan +4 T 1991