002 545 27 05 is certainly the listed part number for W124 with m103 engine from my perspective.

You didn't really mean "1987 300D", did you? I was presuming 300E in all of my comments.

I found 003 545 2405 listed as a "fuel shutoff relay".
This does not mean it would not work, however.
Perhaps a newer listing.
Apparently, it was working for you, at least to some extent...

__________________
1986 300E 5-Speed 240k mi.