1981 320i headlight help

I have a problem that is driving me crazy maybe u can help..... all of the sudden lowbeam and driving lights inoperable highbeams work fine ive replaced ( blinker,highlow switch headlight switch, driving light switch and appropriate fuses and relay on fuse box,all bulbs are new; Question is there another relay somewhere im missing.......thanks for any help you can give. Oh yeah car 1981 320i thanks again Dan