97 Transport turn signal / driving light problem

[palarry]

I have a 97 Transport. Lately the left daytime driving light and left front turn signal only works once in a while. Sometimes it work sometimes it doesn't. Mostly it doesn't work. This is only effecting the left daytime driving light and the left turn signal in the front. The parking light in this same socket works fine. I have replaced the pigtail socket and bulb and it still doesn't work. The right side is working fine.

Any Ideas?

[LMP]

Typical of failed ground return. Check the ground return wire for these lamps; best, connect and run a separate ground to engine block. With a faulty ground return, the low power parking light finds its ground return good enough but high power filaments don't.

[palarry]

Thanks LMP....Where is the "ground return wire" There is a ground wire by the radiator. I cleaned the ground connection and still no luck.

Please explain how I would run a separate ground to the socket.

Thanks for your help!

Larry

[LMP]

CHeck diagrams here
http://www.autolib.diakom.ru/CAR/Pon...NG%20DIAGRAMS/
for external and headlight schematics. Loation of ground is indicated.
The black wire coming from each of the lamp clusters is the ground. There are numerous complaints about corrosion and bad grounds in this model lamp clusters...

What usually happens is this: the parking light ground return makes is way in reverse through the front turn signal filament then to and through the rear turn signal filament to rear ground. Then when the turn filament flashes, the front parking fades out when the turn signal flashes. YOu would not see it normally because the turn signal light brillance covers the parking filament , but if you take the bulb out and look at it possibly with sunglasses, you would see .