you dont need the plug, all it is is plastic, if you have the cluster you should be able to get it to work. for help Ive attached a photo of the old style plug thats in my 87 325e but the cluster seems like its from 83 going from the stamp.
the plug is long but the only part that does anything is right near the shaft, there are a series of hollow bits (top left corner of photo) with the outer most parts broken out on some of them. The plug shows evidence that it started life with a full solid circle as there is tearing where they are broken.
my plug is coded 09 on the end, this end is why its so long, if you look the the left center, you can see on the face of the economy meter there is a small hole above zero mpg and to the left of "02 usa" the end and its number (09 on mine)is usually visable through this.
in that same part of the photo you can see a black plastic ring with small metal bits(backs of outer ring) showing, thats where the breakout ring(on the black plastic coding pin) fits into and does the "coding" bit. looking now at the circuit board where it is attached you see the inner 10 pins soldered, the thing to note about this is that whole inner ring is electrically connected always, (you can see them all connected but with a bit of the green masking material covering the ring trace) and that ring all connects to the trace that leaves the left of the inner solder pad labeled 1(bottom right of 1). so what happens is when the plug is inserted it connects every pin from the inner ring to every pin on the outer ring EXCEPT for what ever pins arent being pushed because your black coding pin has those sections broken out... this mean if you want to emulate having a coding plug inserted into this type of tach you can just solder jumpers to whatever ones for the plug you are supposed to have... in the bottom right of the pic you can see where you would solder jumpers to emulate having a 09 plug like mine... the problem is I have no idea what cuts are on the other numbered plugs or what car is supposed to have what plug. all I know is this seems to work for my 2.7l 325e and future forum readers might find it useful.
the plug is long but the only part that does anything is right near the shaft, there are a series of hollow bits (top left corner of photo) with the outer most parts broken out on some of them. The plug shows evidence that it started life with a full solid circle as there is tearing where they are broken.
my plug is coded 09 on the end, this end is why its so long, if you look the the left center, you can see on the face of the economy meter there is a small hole above zero mpg and to the left of "02 usa" the end and its number (09 on mine)is usually visable through this.
in that same part of the photo you can see a black plastic ring with small metal bits(backs of outer ring) showing, thats where the breakout ring(on the black plastic coding pin) fits into and does the "coding" bit. looking now at the circuit board where it is attached you see the inner 10 pins soldered, the thing to note about this is that whole inner ring is electrically connected always, (you can see them all connected but with a bit of the green masking material covering the ring trace) and that ring all connects to the trace that leaves the left of the inner solder pad labeled 1(bottom right of 1). so what happens is when the plug is inserted it connects every pin from the inner ring to every pin on the outer ring EXCEPT for what ever pins arent being pushed because your black coding pin has those sections broken out... this mean if you want to emulate having a coding plug inserted into this type of tach you can just solder jumpers to whatever ones for the plug you are supposed to have... in the bottom right of the pic you can see where you would solder jumpers to emulate having a 09 plug like mine... the problem is I have no idea what cuts are on the other numbered plugs or what car is supposed to have what plug. all I know is this seems to work for my 2.7l 325e and future forum readers might find it useful.
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