lighting problem?

ive just bought a 1998 renault megane 1.4 rt.the front side light bulbs had both blown so i replaced them.both fine.however i fitted a new tailgate yesterday without having to touch any wiring in the boot.now both my rear night lights have stopped working.the fog light,indicators and reverse lights are ok.the rear light bulbs both work in the reverse light socket but not the rear lights,please help,checked fuse board too.thankyou