I installed mine on the low beams (high beams just too much) with a cutoff switch in the sensor circuit so that I can turn them off during the day if desired. Otherwise the sensor controls them, and per the regulations stops the modulation when the sun goes down. If anyone wants to see pictures of where I mounted the sensor and cutoff switch, just PM me with an email address and I will send pictures of the sensor position and switch (DPST to switch both the sensor wires) I used.