my old orion had same problem,my dads xr3i has same problem rite now and my rst cab also has this problem aswell.
my mate fixed the orion by wedging the 2 relays in a different position.on my dads xr3i we changed the high beam to dipped beam wires around just so he can use it for now on back of headlights.
on my cab ive had to drive it on high beam for now as i ent got round to it. ive played with the relays and doesnt make a difference.must be the contacts in fuse box.
it defo wont be the switch mate