Driver's side front turn signal doesn't light up
 

The driver's side front turn signal on my 1988 928 S4 does not illuminate. I changed the bulb and verified that the fuse for it was good. Do any of you have any suggestions as to how I should troubleshoot this further?

a generic test light would show you easily if your wiring harness is powered at or near the light......if the positive wire has power, and the positive contact in the light fixture has power, start checking the ground for the light fixture and the ground side of the wiring......

you can also use a multi-meter for testing this as well.;)

When you say it doesn't light - is this in the turn signal - flasher mode or in the marker light mode or both?

These are dual filament bulbs - is that what you used for the replacement (21W/5W)?

...oh and we are talking about the corner marker + turn signal right? (next to the fog/driving lights?)
the side marker at the front does not flash on a USA car.

Alan

does the matching rear bulb work? My left side front and rears were out, turned out to be a bad track on the circuit board (both front and rear are fed from the same point). So i had to solder a jumper to cover the bad track

Problem solved! The connection where the turn signal light plugs into the wiring harness was loose. I tightened the connection up and it now works as it should. Thank you all for the help with this.