Navigation Landing lights Etc

Hello

Can anybody help me for some reason or other all the Navigation lights are not working on any of my aircraft which are all default all the otherlighting effects are working ok. I have Go-Flight modules that switch the lights which are activating correctly on the overhead but the lights do not come on.When I press L on the keyboard the other lights go on & Off and it also activates the neon bulbs on my Go-Flight Modules
anybody any suggestions please.

Regards Royann