I need help with my light!!!!

i just bought a 400 watt light. its a switchable ballast so it will work for hps and mh. BUT!!!!!! there is no switch or anything to switch it to hps. i thought it would be simple and u push a switch up for mh and down for hps. BUT NOTHING IS EVER SIMPLE!!!!!!!!


does anyone know how to switch the ballast?

thanks alot

+rep​