Reinhard, thanks for the pics. I pulled out both relays now and opened up the fuel pump relay.
here are three pics.
I inspected the whole relay and internal contacts on the switch. Everything is clean and all solder points are good. No oxidation or hairline cracks etc.
So, I am assuming that my relay is good.
I will re-sheath it ans close with silicone glue for sealing.
The contacts-prongs are clean also.
All resistors and caps look good.
ANY POSSIBLE HIDDEN DEFECTS IN A RELAY?
So, thanks you for your instruction and for all oters, here is an archive of the interior of this relay.
Next is to replace the fuel filter and hope that the fuel pump
is OK. A previous opinion was to replace all parts as per the
dealer diagnosis. Maybe I will go part by part.
Some people have told me that they had many more miles on an original fuel pump than I do. This was posted on my original thread.
1979 300D 199 K miles
1995 C280 95 K miles
1992 Cadillac Eldorado Touring Coupe 57K miles
1979 240D 140Kmiles (bought for parents)
SAN FRANCISCO/(*San Diego)
1989 300SE 148 K miles *SOLD