I was able to acquire a tachometer/clock for a W123 280E. How does the wiring of these things go? There are three terminals on the tach itself. One is marked with a + (+12V I assume), the center pin is grounded to the tach's body, and another one marked with a W-.
Any ideas? I tried hooking up the + terminal to a 12V source and the W- terminal to the negative side of the coil. Nothing.
However, when the center terminal is hooked up the negative side of the coil, and the W- terminal is not hooked-up, the tach works (although a few hundred rpms low).
My wiring doesn't seem right. Anyone?
Thanks and regards,
79 350SE (W116)
86 230E (W124)