I Have A 99 Diamante, And My Foggs Will Not Work, I Changed The Fuse, And Changed The Bulb They Just Will Not Cut On, Anyone No Why???

Given you've replaced what you have, its either the switch or the wiring. Get a voltmeter and see if the wiring has any breaks in it. If its not the wiring, its probably going to be the switch.

If they are after market foggs some have voltage regulators that can be damaged or go bad, and have to be replaced or they wont work.