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Hippo or Others...
I just pruchased an aftermarket tach for my 02' FXSTDI. The tach came with no wiring instructions. There are 4 wires in the tach harness.
-Green
-Red
-Blue
-Black
My first question is: Do I have to tap into the wiring harness under the seat, or is Harley nice enough to supply these same connections under the speedo? Just thought this was a possibility since Harley now makes a speedo/tach-in-one (for a mere $415 smackers) for the bike. If that's not the case which wires go where, and what color are the bikes wires that I should be tapping into? I've heard the black wire on the tach (chassis ground) is best connected to the tach housing itself??

Again, thanks in advance guys!!
TAZ
 

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The bikes have all the wiring right there. The tach wire is pink and is probably hidden under the dash panel. On the baggers it used to be in the nacelle. Just look at the wiring diagram if you do not find it. It has a funny looking plastic cap over the end.

The red on the tach goes to switched power, either the red with a grey (I believe, check it is hot in run only) stripe off the switch or whatever orange wire is close (check it for same)

You need to find out which color wire is for the light, either green or blue but probably blue (just hook the tach across the battery, black to - and blue and /or green to + and see which one makes the lite come on).
Then hook the lite wire to the same wire as the red wire, unless you want to go to the trouble to find another instrument lite wire and hook it to it, no big deal if the tach lite runs all the time and keeps it clean and simple.

The black tach wire goes to a good chassis ground, use a separate ground.

The wire you have left probably the green one but it might be the blue one goes to the pink signal wire from the bike.
 

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Some aftermarket tachs cause problems, if you have some sort of check engine lite when you first run the bike disconnect it inmediately. If it reads either double or half the rpm look for a dip switch on or inside the tach, if it doesn't have one get a new tach. LOL.
 

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Speaking of tachs, I also bought a used Harley tach from an earlier model softail. Three wire connection. I am not an electrician but wondering if the instructions stated by Hippo above, would also work for my 08 Heritage. The thing that concerns me most is that the tach needle is not sitting at zero when not connected. Anybody got any ideas?
 

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Ummmm? Are your tachs made for single fire? All big twins with twin cam engines are single fire, most aftermarket techs are for dual fire ignitions... If not, it will read half engine speed when running, but will cause no harm...
 
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