my exuast fan isn't working???

hey guys i just bought my first light set up and the guy at the hydro shop wired it up, well i just finished setting up my lights and the fan isnt working what could be the problem

what exactly is your exhaust fan?

uh...many things...few more details

heres a pic of what i have

it seems to be hooked up right what could it be

plug it in

lol i did i just fixed it there was a loose wire haha should of tried that first anyways i got another question should i keep my 250 watt hps light 6 inches from the top of my plant

hold ur hand under it for a min .if its hot for ur hand ,move it up a little.