Much help needed - typ. 89 headlights

[alan pritchard]

Hi guys, for the past few weeks/months i have apparantly not driven in the
dark, last night i noticed that i had no useful light coming from my
headlights, when i looked on normal beam only the small side light bulbs
were working, however, when i put the column switch down to side lights i
get both the side light bulb, and a very dim main bulb (just enough to drive
with in built up areas).  When the switch is put back to the top position
and i flip the lights to high beam, the seperate high beam comes on, and the
main beam bulb lights up to full brightness.  This is very weird........
So things ive checked......
first thing was to change the bulb - no difference
Check fuses, as i recall fuse 15+16 (rated 10 amps) visibly seem ok, should
have checked the lights with the fuses out thinking about it
I looked for relays for the headlights, but none were listed under the
bonnet, i know theres some under the dash, but dont know what for

Thanks guys