blinking glow plug light

[Rat407]

I have read through the book on this and can't seem to figure it out. My glow plug light blinks.  It does it while driving down the road. It will blink and then go out and stay out for a day and then blink again, some times it will blink really fast and some times just a normal speed blink. I have drained the water separater under the car, it is a 91 ECO jetta.  No water and I even changed out the fuel filter but it still blinks every so often.  Any ideas on what to check next. No other issues with the car, it runs great and I still knock out 50mpg.
Thanks

[shwartzbewithyou]

Does it seems like an actual "blink" as in is it steady? Computer related (computer controlled?) Or does it just come on and off randomly? If it's more random then I have heard something about the fuseable linkage for it, when it get's old and crusty.
I may be wayyyy off in left field with this one.  Someone care to chime in?

[Rat407]

When it comes on it is a steady blink, but then it will go crazy and blink fast and then slow and not in rythm but not all the time.

[regcheeseman]

Bad connection on the glow plug relay (possible water entry) or glow plug relay itself is faulty.

[shwartzbewithyou]

Ya that's what it was.  Follow the system for the glow plugs and check the connections at all points along the way.  See what you find.

[LeeG]

Its something to do with the water seperator on my car.  light blinks like described above, but it stops if I disconnect the wires from the water seperator inside the trunk.  I have a spare seperator, I plan to dissect it to see what they have inside them for a sensor.

[stewardc]

The sensor goes bad in time. I've had it happen before.