Help! I bought a small tachometer on ebay for my 240 and cannot find a wiring diagram that shows how to hook up the tach. I am looking for either a wiring diagram or hoping someone who has done this before will share their knowledge. Thanks for any help. Stan

hi there,
G on back of guage hooks to red/white wire behing instrument cluster.
+ on back of guage hooks to a key on 12 volt fuse.
- on back of guage hooks to a ground point.
this is by memory. maybe wait for someone to confirm. good luck.

Trust this, the wiring ain't there. The red/white may be OK but I have never used it, but G is for the input signal. You splice bulb ground to tach ground and go to the instrument panel ground at the center console. Instrument light is off the brown wire in the dash. The Volvo instructions call for +1 on the coil to the tach. I do have the gauge instructions for the tach but you should not need them now.

The white/red stripe wire will be there, and will work fine for the signal input. It's the same wire used for large tach installations, and it's long enough to reach over to the small tach location too.

The + and - wires you have to make up on your own.
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Rob Bareiss, New London CT ::: Roterande Fläkt Och Drivremmar!

I've heard that all of the wiring for the small tachometer is already there. In fact, supposedly it takes the same lead that the large tach takes--if it's not already hooked up, then behind the instrument cluster there should be a loose double wire not connected to anything. I think it's got a spade connector and has a red and a white wire. Move it over to the center console area behind your tachometer and connect it up, and it should work.
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'89 244 GL -- 110,XXX miles (see profile for info on car)