Might want to check your OVP, my car had the same prob, one of the fuses was blown and it would not activate cold start. Also check voltage regulator, mine was very worn, $30 and 5 mins to replace. Possible accumulator.

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1981 300TD
2005 C55
2004 E500
1999 ML430
1992 400E
1998 C43
2001 SL500
1988 300SEL
1986 190E 16V
1991 190E 2.6