rear lights not working

[ryan17hurley]

my rear lights dont seem to be working propely

the rear indicator on the left isnt working

and the brakelight on the left isnt working ethier

i have replaced the bulbs and still not working

i think its a wiring falt, what should i do

 

[fast5]

bad earth on the rear cluster?

 

[Hutchie]

sand paper and a bit of wd40