question about current

 Looking at the wiring diagram I'd suggest a few things..

 First, if the high beams are working, this validates the wiring up to the headlights.. if when you activate low beams you're still getting 12v at the headlight terminals (wires R/B and R/BL) then the relay is still activated.

 When you activate high beams, does the high beam indicator illuminate on the dash?.. It appears that the high beam indicator is fed off the low beam circuit.. is the high beam indicator 'on' all the time? Does it ever come on?

 Probe the terminals of the multifunction switch.. with the high beams 'on' the wire R/Y should be at ground potential and the wire R/G should have 12v. With the low beams 'on', wire R/Y should be at 12v and R/G should be at ground. Post your findings please.

 These tests will narrow down where the problem lies..

 Regards,

 Jim