cooling fans not working... HeLp!i!i!i!

ok... my car... 94 integra LS... i busted my radiator the other day... so we bought one from the acura dealership and me and my dad put it in... and everything worked... but he wanted 2 put a new thermostat in 2 be on the safe side... so i bought a medium temperature therm. for my car... we put it in 2day... and now when i turn the car on... NEITHER one of the radiator fans come on... we didn't unplug 'em when we put the new thermostat in... so does anyone have any ideas? shouldn't one fan come on when u turn the car on?? help please!!