Blue/white tach wire signal voltage?
 

Any way to test signal voltage from this wire? Have a customer who's tach isn't working even with direct wire connection....

I'm the PITA customer :D


From further reading on installation of custom tach's on motorcycles, most seem to point to potential grounding issues. I do have a multimeter handy which I will use to find out if there is any voltage going through the line...not sure what to look for because I believe the signal is sine or square wave for RPM's, which may not be measurable on a standard multimeter.



Any input appreciated - I initially used the wire splicer and tapped into the blue/white wire per instructions, the cluster appeared to be working fine from initial testing (I hadn't started the engine yet though). Once I fired up the engine for the first time, I noticed the RPM's weren't registering on the tach. I spliced into a different part of the blue/white wire (that also didn't work), then soldered the wire from the Cluster directly to the blue/white tach wire on the Hawk. Still nothing. That eliminated the splicer as the potential cause.



I posted a video on YouTube to show what it's doing - everything else works great - gear indicator, fuel sensor, turn signals, the rest of the cluster is functioning as expected.


https://youtu.be/1XZSt7ZxnVs

You should see something on the meter that changes with speed. Different meters will see pulses differently so you can't go by the actual voltage. Use VDC tach lead to ground.

If that doesn't work try VDC from +12V to the tach lead as they could be switching the ground instead of hot.

So multimeter pins on the tach and ground wire first to check voltage, and if that doesn't register anything, tach wire to the +12V battery lead? Just wanted to make sure I'm on the right track. Thanks llr...

I don't know if this will make a difference for the tach not working because I haven't tried it. But I noticed the 21 inch wheel size popped up n the display. From what I recall that will only come up on screen if you disconnect the 12v power lead. Check the positive lead and fuse for the cluster. :shrug: Just a thought.

I noticed the same thing. It looks like it is wanting to go into the setup mode, almost like main power is not present.

Good point! Make sure the putz that assembles these has installed a fuse in the fuse holder!

yes, I would check the fuse and setup mode as suggested.

Basically you are looking for a change in voltage with speed. The only true way to see what it is doing is with an oscilloscope which not to many people have anymore.

If you post the brand and model of the meter then if someone has the same meter and would try it then the readings could be compared.

Thanks guys - that 21 definitely comes up every time in the display. Glad I posted the video - a picture is worth a thousand words, videos...a million! I'll make sure I check for a fuse!

Affordable / very rough result only :doh:
https://www.youtube.com/watch?v=SNXX-jk5ay4

I did more troubleshooting this afternoon - the Cluster gets power without the lead (long cluster cable that routes to the rear of the Hawk) connected to the battery, so it's already getting power from one of the wires in the stock plug. Matt did make an edit stating that the rear cable may not even be necessary since the wiring on the new Hawks was already routed up front to the stock cluster.



The "21" shows up during initialization with or without the rear cable plugged into the +12V battery lead. I de-soldered the wire from the rear cluster cable and disconnected from the blue/white tach wire thinking it may be connected redundantly (I believe 2017 and newer Hawks already have a tach feed up front). However, this didn't make a difference. No RPM readings from the tach when powered on with the engine running. I also replaced the fuse on the rear battery lead with a brand new fuse just to rule it out.



Next steps are to test signals/voltages from the wire itself to see what's going on, as well as checking the ground (if the ground was an issue I don't think the Cluster would work properly at all).


Not sure if the voltage is being stepped down somehow from whatever power lead is connected up front. If it absolutely needs power direct from the battery terminal then maybe it's worth trying to disconnect whatever power lead is running up to the front and powering the cluster through the plug.

I doubt if the voltage would be stepped down up front but that is easy to see with your meter.

Chris, did you try unplugging the connector at the rear of the cluster and check for bent pins?

I have not unplugged it and will give that a check - definitely a good suggestion.

This problem has been RESOLVED. Here is what was causing the tachometer issues...

The factory wiring was incorrect on the digital cluster. If you look at the two photos below, the first is a BEFORE and the second is an AFTER shot. The blue/white wire from the digital cluster was actually crimped to the RED battery lead wire. The purple wire, which is supposed to get power from the battery, had the wire splice terminal on it (which I had since removed). I never bothered to notice this. The purple wire had the wire-tap terminal which is what I was trying to plug into the blue/white wire. Of course this caused the cluster to display the "21" as those who posted about the battery lead missing were in fact CORRECT. The tach wire was swapped with the battery wire. I spoke with Matt and he said this mix-up has happened before. What made troubleshooting difficult was the fact that my cluster was getting power, so it looked to be functioning.

Before... (see the issue??)


https://s33.postimg.cc/u0l5zvanz/20180730_160914.jpg


After - soldered both wires. I used heat shrink to seal the connection to the battery lead, and just electrical taped the soldering for the tach wire since that was more of a mess and not able to be heat shrinked. Everything works flawlessly now...tach functions normally. Problem solved.


https://s33.postimg.cc/sljlb5han/20180730_161920.jpg