Drivers side front signal not working right

Hi I'm working on the wiring of my 72 bus. I got all the lights working correctly with the exception of the drivers front signal light. The running light part of it works, the signal light only works when the lights are off and not very good . Any ideas?
Thanks
Rick

 

Have you checked the brown earth wire that is screwed into the headlamp bowl has a good contact?

 

^^^^ X2

 

Yeah agreed,,, most electrical problems are down to bad earth

 

Earth, earth, earth. ...When a little light bulb works in a cluster when the larger light bulb is switched off, it is earthing through the bigger bulb in series with the bigger bulb's counterpart on the other side..
The proper earth wire for the front indicator comes out and is screwed to metalwork nearby. If you miss it out it might have been happening to earth for a while through a screw which has now corroded...