application
The high beam may be blown. ---- Bad relay.
If only one beam isn't working, it probably isn't the relay. More likely, it's in either the harness or the wiring.
I do not know about the SL1, but often there is a relay for high current circuits such as headlights. You could check for proper operation of the high-beam headlight switch at the excitation terminal of the relay and check for headlight circuit energy at the output on the relay.
Bab bulbs? (they are double filamented) Bad dimmer switch? Bad low-beam relay?
Bulbs burnt out (they are double filamented low beam may be burned out) Bad dimmer switch? Bad headlight switch? Bad low-beam relay?
if your low beam lights run off a relay, then that might have expired. will need replacing if it has.
Bulbs burned out? Bad switch in multifunction lever? Bad Hi-Beam relay?
It's ether the switch/wiring/bulb/relay. You will need a multimeter to diagnose everything but the relay. You can swap relays from something else to see it it works.
Bad bulbs they are double filamented perhaps one filament burned out Bad switch Bad Low beam relay
Do you flip the hi beam switch and it's still on hi beams or no head lights are on in the switched position/ Find the headligh relay and swap it out with a another relay
High beam light is out!
how the apfc relay work