On the bulkhead adjacent to the bonnet latch is a multi-bladed earth attachment, looks a bit like a metallic spider. It is held in place by a 6 mm machine screw in the centre and if you take it off and clean up the mating surfaces you may have some joy. When I bought my 33 sportwagon (in 1993) I had something similar to that which you have experienced and as I'd only had it a couple of days I really thought something major had happened. If it isn't that earthing point look for another. In the meantime I'll have a look in the workshop manual for one.
Update: had a look and according to the earlier w/shop manual all of those above are serviced by fuse no.5 (except for the radio no.4). Count from the right with the group of four separate fuses towards you. Take the fuse out to inspect it as they are notorious for forming an almost invisible crack. Supplement for w'shop manual shows no.4 for radio, cigar lighter and horns; no.5 for interior lamp and indicators; no.7 for power window relay, clock and rear wash/wipe !
Last edited by armoore; 12-01-13 at 13:13.