I just got my new speedo in and it has a blue wire coming out of it. Stock one has no wires coming off it. I was thinking its for illumination but not too sure. Any one else got ideas. Thx.

 

What bike do you have? I last replaced my speedo around '02 ...I think there was one wire and if I remember right it goes to 2 or 3 lights in the speedo for my 86 flst.

 

its an 88 fxsts. im just not sure which lead i should be puting it on the ignition. my manual dont show and there was no info. provided iwth the box

 

If the speedo is for a '91 or later, it will have a short wire coming out of a rubber grommet which runs from the reed switch in the speedo to the turn signal module to tell the turn signals when to shut off. If you try to use a '91-'95 speedo on an '88, you'll find that the trip odometer reset **** won't line up with the hole in the dash cover, and you'll also have to source a '91-'95 dash cover as well.

The only other wires on the mechanical speedos go to one or two lamp sockets located at the 12 o'clock and 6 o'clock positions of the dial. The sockets snap in and out with a sideways push.