Horn and light snag

[scotty_d]

Just a quick question to see if this is common before i start looking for the cause.

I just fitted some HIDS to the cerb and noticed that when i use the Horn the left hand dipped light flickers and the horn is really rubbish struggles to work so thinking a bad earth bad earth? where are the earthing point on a cerb? will check and clean all connections as well.

Cheers Scott