I know there have been posts about this. I know you might all wanna call me bad names. I searched the archives and found not alot on the small tachs, just the large ones. I am looking for clear, concise and complete instructions for installing a 52mm Small Tach I just got from E-Bay.

On the Back at the top is the wiring for the lamp. There is a BLACK wire and a GREY (or really faded WHITE wire).

On the Back at the bottom is a Three wire group or cluster. The BLACK wire from the lamp comes down and plugs into the Negative Side of the 3 wire grouping. There is a RED/BLUE Wire coming off the Positive Terminal. There is nothing on the terminal marked "G". Please help me out with clear and complete instructions if you can. I would be more than happy to make a Wiring Diagram for the Board for future reference since this is not mentioned in the FAQ.

Todd :-)
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'90 245 182k

Piece of cake, the red/blue wire has a + at the base of the terminal, it goes to a switched positive at the fuse block, #12 is usually a good choice. the "G" gets a signal from the red/white wire behind the instruments, you can also run a longer wire out to the #1 terminal of the coil. The black wire from the light and the wire from the - terminal goes to any ground screw, I usually use the large screw at the upper left corner of the center console. Power for the light is taken from any of the brown wires to the lights in the center console. Setup this way the light will dim with the rest of the instruments and the tach will only get power when the car is on. The light in the tach may be bad, most are by now, it is available at any import parts house, it's a 12v 2w take the old one in and they should be able to find it.
Good luck.
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Dave Shannon
Spring Valley, California (San Diego area)
'84-245 200K+
'84-245T 190K+
'88-240 190K+
'92 745Ti 150K
'01 Jeep Wrangler Sahara 10K
www.volvo2.homestead.com

Does anyone know the characteristics of the tach lead? I've about given up finding a small tach and would be willing to build/convert something if I knew what tach speed corresponded to a voltage or current. Anyone know?
Thanks.

Have you considered the larger tach? They're pretty easy to find at most junkers. There's a chance i even have one kicking around home......