I took out the properly working cluster on one of my 300SDL's to refresh the needles on the gauges. At some point the cluster has been out prior to my ownership as the main plug connector was broken (glued it back in properly).

When I connected the cluster back in, there is a definite problem. When the key is put into the on position, the oil pressure seems to be getting the fuel readings, the temp gauge the oil pressure and the fuel gauge shows empty with reserve light illuminated. Initially when I turned the key on, the speedometer was getting power and registered 20 mph.

I took another working cluster from another 300SDL I have and it does the same things when connected!

Anyone have a clue what is going on, and exactly where I need to look to resolve this problem?

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Mercedes Fleet:
2004 CL600 Designo Espresso SPORT
2004 S600 Designo Espresso SPORT/Lorinser Pkg.
1999 S320
1988 300TE
1972 280SEL 4.5
Diesel Fleet:
2014 GL350 Blutec
1987 300SDL Blk/Blk 4 place seating #18 head
1987 300SDL Smk Slv/Burgangy #17 head
1986 300SDL Blk Pearl/Palomino #14 head w/ 280K
1984 Lincoln Mark VII Fact BMW Turbo Diesel