Greetings all,
I was wanting to install a early smaller tachometer in a 1980 240. I cannot locate the red/white wire as the later models have available. I see a red/white wire coming from the coil but it seems to go to the #3 pin in the round cluster plug. When I tested it for power there is no power at this wire while car is running and round plug loose. When I attempted to attach another wire to the same plug on the coil, that the red/white comes off of, the idle drops substantially when this wire is grounded.
Is there a tachometer wire behind the cluster hidden somewhere?

Thanks in advance,
Joseph in sunny New Mexico