Funny this happened to my '77 240d as well.. Got it started by cranking thursday, but the master cylinder went out on my way home from work .. rather unpleasent.

2 Days ago I checked, the GP light came on, and the car fired up nice. Last night I changed out the MC, wanted to go take it for a test run but again the GP's wouldnt kick on.

Is there something I should check that would cause an intermittent GP failure, or is it pretty much limited to a bad relay?

Fuse is solid from what I can see, I do have the older loop style plugs. Anyone have a good source, or a part # for pencil plugs that have the right fit?