yeah i know how it feels to have people view and not answer but let me see if i can help with my previous experiences.
it may not be a relay itself but another fuse that can cause your city lights and or fog lights not to work. check all fuses before resorting to a relay. i would pull them all out and then put them back in their original location. i can't tell you how many fuse locations you have since your a 450h but i do know for fact the other fuses can cause the problem (i.e. "left control switch" the switch for the headlight/fog. it may have a seperate fuse that the fogs/city lights itself) so check all your fuse locations and make sure all the fuses are not blown.
hopefully that helps.
and i dont mean any insult to this at all but are you turning the actual fog light switch where the headlight switch is? im just saying because it took me almost a full day to try and figure out where the fog light switch is.
i kept looking for it in that drop down box our cars had. lol