I have an 07 Dyna CVO. I have been having issues with my speedo not working properly. This started about a month ago. It would be working fine and the needle would drop about 30-40mph for a second and go back to normal after. Sometimes this seemed to happen when hitting bumps in the surface of the road. I thought maybe a connection was loose or something. However, I haven't been able to find anything like that. Lately, it has started going periods where it doesn't work at all or that the needle drops all the way to 0 for a period then goes back to regular speed. It seems to not be working more than it is working at this point. I am not using OEM speedo and tach stack that came on 07 CVO, but I have not had any issues with this for over a year since it was changed. So, I do not feel that has anything to do with it.
Can anyone give any pointers on what to check or what this could actually be? What controls the speedo? Does it run off the ECM? Is there a speed sensor mounted on the tranny? Please help!!!