Tachometer

[71-F-250SC-72-F-250C]

I just bought a tachometer, and I have all the wires hooked up, except for the red one. I have the green one connected to the negetive side of the coil, the white one is hooked up to the fuse box, where the light fuse is, and the black one is grounded. The light on the gauge works, but when I turn the key on, the instructions said the gauge should move, but it does not move until the I turn the key off. I tried starting the truck and the gauge does not work. I have pictures of 2 places I have tried wiring the red wire. One was to a fuse, like I have the white wire hooked up, and one is to a wire coming off of the ignition. Maybe you guys can look at the pics, and see if you can find the wire I need to wire the red wire to, or the fuse I can use.

Thanks, Stephen

[Freightrain]

Usually the RED wire is to ignition HOT. So it powers when key is ON. Usually there is an extra HOT somewhere under dash that comes on with key. The radio wire is a good one for key on power source. The fuse panel is hot always so that is not a good place.

If the WHITE one is the light, then it needs to go to dashlights so it comes on only with headlights. Or it will be on always if tied to fusepanel(that's ok if you want it that way).

I take it you have no instructions for tach? Hence the problem with wiring?

[71-F-250SC-72-F-250C]

I have instructions, Im just not that good at wiring. I did get it wired up correctly though. The light only comes on when I turn my lights on, and the red wire is also wired right. I found out that the only problem I had was that I accidently hooked the green wire to the positive side of the coil Also, aren't you a member from FTE, I seem to remember your avatar, you seemed to be pretty helpful over there as well.

[68F250]

Ah ha! I was gonna say your tach was broken, glad you found the problem.

Instead of running the white wire to the fuse box, tap it into one of the wires for the dash lights. Then you can adjust the brightness of the tach light in unison with the dash lights instead of it being full on.

[Freightrain]

Ya, hooking it on the wrong side of coil will do it....LOL!!! Glad you figured it out.

Yup, I'm all around.........Nationwide........LOL!!!

[71-F-250SC-72-F-250C]

I wired it up to the fuse box like that because I do not want to cut into any wires on the truck. I wondered about the wires coming out, but they seem to hold fine. The tach can also be removed, without anyone knowing it was there.