rear light not working??

[mtbrider0]

i came to change a fog light thismorning to the rear right light housing, changed the bulb with the power off and when i came to check the light i found none of the rear right housing lights were working :S i thaught it may be a loose conection but i check that, still not working. i read on anouther forum that it might be due to a loose or coroded ground wire?? where is the ground wire located?

thanks

[mtbrider0]

solved!! was due to polluted bulb conections. fixed by cleaning the conectors o0n the bulb.