Planning the next
AO Silver Member
Join Date: May 2007
Location: United Kingdom
As the mains are working, you can probably rule out a bad earth. Also, as each bulb has it's own fuse, that's likely to not be the problem ( although do check ).
My inclination would be the dip beam relay. Both the main & dip relays are on the main fuse panel - left hand side, top and bottom of the 3 relays. Put your finger on one and switch on the lights on both main and dip. The main beam relay will click ( you'll feel it ) at least. If the other one doesn't click, swap the two relays over. If it is the relay that's at fault, the dips will then work and the mains won't.