Would any electrical expert here know why my HD mini tac that is mounted on center handlebar would have the needle jumping all over when installed? I am having the HD Dealership install this and they told me this. They were going to look into problem next week. This tac is only a year and half old. Bought new and Dealership installed it on my 2012 Sportster 1200C. Now sold that and wanted them to install it on my 2012 Super Glide Custom.
Any help would be helpful to relay on to them.
Thank you, Kurt

 

not poking fun or anything just sayin... if you don't have enough faith in what they're doing for you that you have to come here and ask, then I'm not too sure I'd be letting them touch my bikes.

Couple of things to check right off the top of my head;

First and foremost check all ground wires especially the ground wire from the battery to the frame. Clean any corrosion and make sure it's nice and tight.

2nd would be the connection at the ECM is not secure. Should be pin #3 at the ECM

 

^^^Something's amiss^^^

As UltraNutZ recommends - check the continuity/connections. Tach shouldn't jump so there's got to be an interrupt/break in the signal...somewhere. Good luck & don't let the dealership say it's "normal" because it's not.

Maybe download & look @ tach install specs 1st...then you know where the connections run/terminate for troubleshooting.

 

I know, just want to get bike back without them telling me I need to pay them to install a new tac.

 

hope you didn't take offense as none meant.. good luck and let us know if we can help.

 

None taken, thanks for information.

 

Just found a post that says now #2 at ECM should be used on Dyna bikes. Not the #3 at ECM. Has anybody tried this on their Dyna bikes? Guess the bike it worked on was a 2006. Got that jumping needle issue. On my 2012 Super Glide.

 

2012 and up Dynas have a CAN (controller area network) system. ECM for these models changed as well.

 

I see you have a tac wired on your bike. Would you know exact bike wires used to make your tac function properly?

I'm just angery at Harley for lack of information on instructions (outdated info.) as well as Dealership on how to wire up a simple tac!

 

Sorry I can't help you...I checked a 2012 Dyna wiring diagram; ECM doesn't show any tach or speedo connection point.....