See Controls and Indicators → Accessory Switch → Switch Indicators. Use the auxiliary lamp switch (1) to turn ON the auxiliary lamps as required.

NOTE

On the FLHT/C/CU, the auxiliary lamp switch (SPOT) is on the left side of the ignition/headlamp key switch on fairing cap.
On the FLHR/C the auxiliary lamp switch (SPOT) is on the right side of the triple clamp shroud.
The auxiliary lamps (SPOT) do not work when the headlamp is on high beam.