Tach install wiring questions
 

I just received a Custom Chrome Mini Tach from an eBay auction. It came without any wiring instructions. On the rear of the tach at the bottom there is a black wire and a blue wire, the blue wire is grounded to the case. I assume the black wire is for the light. At the top of the back there is a three wire combo coming out, a red wire, a black wire and a green wire. I assume the red is power, the black is ground and the green is signal. Am I right? And to what do I attach the signal wire?

Help!

Thanks!

RE: Tach install wiring questions
 

Here's some info for you..

https://www.hdforums.com/m_102190/tm.htm

And for the signal
https://www.hdforums.com/m_65101/tm.htm

RE: Tach install wiring questions
 

Thanks, TC. If I am lucky, I may find a working tach signal at the speedo, if not lucky then at the ECM connector. Is it safe to assume that this tach uses the same type of input signal as the tachs noted in the two articles you cited?

Another question...if the black wire that is not part of the three wire cable is for the lights, would it make sense to just splice this into the red wire in the three wire cable? No reason to have lights separate from tach power since the machine is lit all the time the ignition is on anyway. What do you think?

Thanks,

RE: Tach install wiring questions
 

Most tachs do use the same source after the 03 model year.

You could do as you stated above with the black wire, I would rather hook up to the lighting circuit myself.

RE: Tach install wiring questions
 

Well, the tach is installed, and the two threads that TCSTD gave me were a big help. I ended up taking the tach signal from pin 3 of the ECM plug. The plug does not have a socket for pin 3, so I bought a 72076-00 pin socket from my dealer. Cost me $1. It is easy to put in, just follow the directions in the electrical service manual or in the threads that were cited.

I took tach power and tach light power from the orange/white wire going into the speedo, this is fused at 15 amps and is powered whenever the ignition switch is either at "on" or "accessory". The black wire in the speedo cable is ground, and I used that for both light and tach ground. I split the wiring bundle cover, pulled the two wires out a bit, shaved off the insulation from about 1/4 inch of it, carefully pulled the copper conductor away from the rest of the insulation, and soldered in the tach wires. Then I covered the splice with some electrician tape, then repaired the bundle cover with the tape also.

The tach signal wire I threaded down the front of the tank and underneath back to the ECM plug. This was a major pain, but it made somewhat easier by using a piece of soft wire with the tach signal wire fastened to the end of it and then pushing the soft wire through the various wiring supports under the tank, carrying the signal lead with it. (I was too lazy to pull the tank). Once I had the wire routed, then I took some silicone tubing (model airplane fuel tubing, fish tank tubing) and forced it over the wire under the tank so that it would not chafe and short out. Then I routed it neatly to the ECM connector and crimped it to the new pin, which slid nicely into slot 3.

Put it all back together, and it works just fine. Here's a photo of the finished installation:



[IMG]local://upfiles/6644/1CE55EC5DDDF463082C012666E5F541A.jpg[/IMG]

RE: Tach install wiring questions
 

I'm glad you got it fired up Tom. Good for you!;)