I posted not too long ago about adding a handlebar tach to my 2007 Low Rider. The first tach had too many wires, so, I got another one with 4 wires. The instructions for the colored wires are:
Green to neg term of coil or CDI..of course on my bike there is no neg wire on the coil
Black to ground
Blue to lamp on..this one I tapped into the original tach harness using the O/W accessory wire
Red to ignition on...this one I tapped into " " " using the O ignition wire.
The above green wire is the wire that needs the tach signal. The only wire avail on the original tach harness is the LGN/V datalink wire. Turned the ign on..lites on the tach came on. Then started her up while touching the Green tach wire to the LGN/V wire. The needle moved between 1K and 2 K on the tach. It wasn't steady. As I reved her up a bit, the needle did not move above 2K; kept on moving between 1K and 2K.
I had a handlebar tach for 2 yrs hooked up as above (I think) and it worked fine before it went bad.
ANY IDEAS out there? I do had the schematics for my bike.
Thanks

 

I'd start by learning how to spell dilemma first and go from there. Maybe a Shop manual should be in your future?

 

Actually, I did google dilemma, and it didn't come up with the correct spelling. Anyways, to make a long story short, the data link wire lgn/v gave a signal but it made the tach needle 'pulse' and didn't increase as I turned the throttle. So, I tapped into the be/o wire down by the ign coil. The tach needle was steady, even tho the reading was in 1/2. eg...idling at 500 rpm, instead of 1000. I read in a previous post, that that happened to someone else also, and they mentally multiplied by X2. That's just fine with me..bottom line is that I finally have a working tach again on my handlebars!

 

So, my mini tach won't work on my 07 low rider. The tach is looking for a analog signal; from what I've read on my previous answers to my post, HD only puts out a digital sig. So....I'm just going to take it off. BUT my check engine lite stays on. The diag code is"low tach sig". I cleared it, but it comes back on. The bike originally had a tach, but I took it off, sold it and bought a mini one. I hope I'm not stuck with that annoying lite on for the rest of my life! I'm a little worried that if something goes wrong and the 'check engine' icon is supposed to light up, I won't know that something is wrong because it's on all the time. Any ideas out there

 

What bike did the tech come off ,you will need a manual from your bike and the manual from which the tech came from.

 

If you've had it hooked up wrong this whole time, you may have burned a part out on the main ECM I/O... or you forgot to plug something back in ....

 

This is your best friend I found mine now it's your turn. This will take out all the guessing answer a lot of the questions.

 

got a manual....not a lot of help, I do know to read the elect schematics. Went to MMI in 74.WRKD, the original tach was off my bike 07low rider. No 'manual' with the after-market tach.Archer...I never plugged anything into the ECM. the #3 input/output was empty a plug on both sides.

 

I'd dump the after market tech and buy a used harley tech from eBay it will be way easier to figure out. The manual show what each wire does and goes.

 

The serial data wire is not the wire you need for this tach, it was probably the one you needed for the last tach you had with too many wires. Do some searching there's been plenty of people that have made those tachs work. I believe there's an unused port on the main ecm plug that you can tap into or a pink wire you can splice into. I'm not sure but I've seen plenty of those threads here