'88 240 DL

Parking light not working.
Predominant signal failure (rapid blinking when not working).
Both on drivers side front.
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A post suggested a ground contact problem.
Cleaned the ground contact and body and applying dielectric grease to mounting screw and both sides of ground contact ring.

That worked for the parking light!
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signal:
No change with cleaned ground contact.

Another post suggests the bulb may be bad. But it does work sometimes.
It seems to self correct when it blinks for a long time - as when I am sitting at a stop light waiting to turn - possibly because something is getting warm and increasing conductivity (?). When it self corrects it goes back to normal flashing interval.
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bulb failure light:
So is the bulb failure warning light not coming on because there is/was some current moving through the bulb(s) but not enough to turn them on?

Thanks