Right.
You need to get an original diagram for the beast before you start chopping it about. However, Normally lights work like this
(Switch) (Contacts)
l ---o
a) + supply ---------------l----o o off
b) o--------------------Side
c) o--------------------Dipped
d) o--------------------Main
Position "a"
Off
Position "b"
Sidelights
Postion "c"
Sidelights and dipped beam.
Position "d"
Main Beam
Notice that dipped and main beam are not connected at the same time!
There are probably relays and diodes in the circuit that operate the lights but duplicating the switch layout will fix the prob.
Byz