So underneath the manifold when I removed it I found an electrical connector that was not plugged in. Coming off of the big harness in that area are 2 that go to the injection pump, and 2 that go to the vacuum flappers. The one additional one is the one I am wondering about, if anyone with om606 knows or can look.

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1990 300d 2.5 turbo
1995 E300d

OM606 came in few different years and models and they all do differ in engine harness configuration, one way or the other.

I was asking about the 94 or 95 w124 om 606.

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1990 300d 2.5 turbo
1995 E300d