Recently I have started experiencing intermittent functioning of the dashboard glow plug light on my '95 E300D. It may work for several starts, then fail to light for the next couple, or alternate between lighting and not lighting. I am trying to determine if this could be caused by the glow plug relay, indicating it needs replacement, or if it may simply be a wonky bulb. I haven't yet pulled the instrument panel to check the bulb. I have not had any issues starting the car when the bulb does not light (tho I'll wait for a couple of seconds before starting if the light doesn't come on), but the weather hasn't been wicked cold yet. Has anyone experienced this issue?

Note that all the glow plugs were replaced with new earlier this year and the engine wiring harness was replaced last year.

Tom
Closter, NJ