strange problem with lights.

[bigyagi]

ok, last week, the headlamps would light, but would not pop up, then they started going up and down all the time!! so, popped into a shop, and when i came out, right side lights are out. hmm, fuse #13. put new one in, and off to the races. i get home and with just the side lights on {position 1 on switch}, i also have my foglights on, but not bright!!! and if i switch the fog light switch on, they are, of course, normal brightness. how can they be tied into the sidelight circuit?? this is beyond me again, like most things electrical. any ideas{apart from sell it, that is!!}
damn electrickery.