My 2002 FLHTC had recently began having tach issues, I saw a couple related posts but was wondering if anyone ever found for certain what was causing the bouncing needle. It is an intermittant issue that seems to get better as the bike warms up and I'm on the highway. Occasionally the needle will rest on "0" RPM's but a downshift gets it working again. I did the simple check by pulling the batwing and checking for a loose connection but all seemed OK back there. Don't think it should matter but they are the Silver face gauges that Harley sells. thanks for any advice.

 

Same thing on my 02' If i turn to the right mine comes on and to the far left she goes to 0. I want to see where this goes. I to would like to know if SG gauges and from what years are plug and play on the 02'

 

check the large plug in connectors in the faring.... i lost headlite and passing lamps ,,,,had the speedometer bouncing,,, little tab that locks the harness plug was missing(i just happened to bump the wires and lite came on) i put a zip tie around the plug to keep it tight......(looking at the inside of faring, plug was on the right side of the radio)

 

First things I would check are connections, but, I had the same issue on mine a few years back. Was a bad wire in the harness at the neck.

 

Another thing to consider is that bad stator caused my tach to bounce around as you describe. However, after a short time the tach just failed to register any rpm.

 

Mine did that and it turned out to be the plug in for the ignition switch was loose.

 

To add some confusion, I've noticed that when the tach is bouncing or at zero, a shake of the handlebars when riding( not recommended)it will correct the problem. Also, I tried the bar shake when the tach is operating correctly, and it will make the needle bounce. I checked the connection into the back of the tach and it "seemed" fine. Gotta love electrical issues.