Seemingly randomly, the stock tach on my 2013 CVO Road Glide stops reading accurately. It's not that it stops working entirely, but rather the readout is a fraction of the actual rpm and the needle response is lethargic. When this happens, it reads near zero at idle, half (or less) of the actual rpm, and hitting the throttle results in sluggish & partial needle movement. This happened once within months of it being new, then not again for over a year. It seems more frequent now, but still random and maybe on few times per month. The bike runs fine when it happens, and only the reading is wrong. I haven't a clue where/how to start diagnosing this. Any suggestions???

 

Anyone with some words of wisdom?

 

Since it is electrical servo motor driven like the speedometer, it may be the connection (hopefully). Mine seems to act crazy when it cools down in the fall. However, it works fine up to about 2500 and then it bounces 4 or 500 back and forth.

My guess is if the ground is good and the connection pins are good at the meter and wherever it's driven from, (speedometer is my pick up..some come off the ECM) then it's the meter.

 

If you plan to diagnose & repair yourself, first thing you should do is purchase a shop manual & the electrical diagnostics manual. Read them, find the area/issue & then follow the troubleshooting as best you can (electrical issues generally require the use of a tester/breakout box).

 

The electrical diagnostics says to check connections. Then it says, replace instrument. (2004 does) which is probably the problem.

The BREAKOUT BOX (Part No. HD-42682) and INSTRUMENT
HARNESS ADAPTERS (Part No. HD-46601) connect to the
speedometer connector [39] or tachometer connector [108].
Used in conjunction with a digital volt/ohmmeter (DVOM), it
allows circuit diagnosis of wiring harness and connections
without having to probe with sharp objects

If problems are intermittent, wiggle harness while performing
tests.

 

I've got a shop manual, but not the electrical diagnostic manual. Sounds like verifying the integrity of all related connections is the place to start.