front turn/side marker question

On my 77 cj5 I have an odd problem with the left front and left front side marker light and turn signal. The right side and all rear lights work properly.
When I turn the lights on the front left parking light comes on ok but the left front side light barely glows. When I turn the left turn signal on the side marker light flashes but the front signal goes completly out and does not flash at all. Figured it was a bulb filiment touching the other filiment, changed both bulbs...no help. Logic and experiance says it is a ground problem but I have not found it yet.
Any ideas?
Ron

 

keep searching for the ground.