Interesting story. I have an '81 240D and my problem with the indicator lamp is that it will light up briefly and then go off, it does not stay on for the normal amount of time. I just count to 10 and start it up. Always fires right up and runs good, so I assume that the plugs are fine.
Sometimes when I'm just driving along the light and buzzer or just the light will come on for 5 - 10 seconds and then go off. I know the PO toasted the relay, replaced it and at the same time put in all new plugs. I bought the car immediately after that. I suspect he toasted a few other things but I have not wanted to tackle it as I have had bigger fish to fry with this car and all seems to function OK. Well, except for the lighting/buzzing issue
