Speedometer acting like a Tach...

Discussion in 'Electrical' started by torch947, Jul 14, 2013.

  1. torch947

    torch947 New Member

    3
    0
    0
    Going crazy trying to figure out what's causing the speedometer to act like a tach, the bike is a project bike using an 02 deuce EFI 88 ci. and ecm and tsm and VR also from 02 deuce. the harness is for an 04-06 softail using a new speed sensor and new speedometer. I read the voltage off of ECM and holds solid at 5 volts I rang out the grounds to the dash and they seem fine, any suggestion's?
     
  2. SilverFoXD

    SilverFoXD Active Member Contributor

    382
    28
    9
    I may be way off base here, but take a look at the wiring harness and the wiring diagram in the HD Service Manual. I'm looking at the manual for an '07 Dyna but the Softail probably is the same.

    The data link/bus wire is light green/violet (lgn/v) and comes in on #2 of the plug to the speedometer. It is also #2 on the tachometer plug, if a separate unit, and they are the same data link. Check the signal there, at the plug. I don't know what the signal looks like, but it should match at the ECM, TSSM, and the speedo. The wire colors should be the same throughout; #7 on the plug to the main harness, #3 on the TSSM, and #5 on the ECM. Again, the Softail may be different but this is what the Dyna diagram shows.

    Might want to check with the HD parts people to see if there was any change in the speedometer or harness between these years. One of our electrical experts should be checking in also.

    Let us know what you find out, and how you fixed it.
    .
     
  3. torch947

    torch947 New Member

    3
    0
    0
    Thanks for replying there were changes the 04-06 was different from 99-03 then in 07 they changed again. So after reviewing the wire diagrams I have, I see the black and yellow up to 03 then in 04-06 it changes. I am starting to think that by using the 02 ECM that this may be my issue, I know I have a P1651 which is Check engine light open which would make sense because on diagram for 99-03 the light comes off of the ECM on 04-06 it doesn’t that pin is open. Also on 01-03 I see that the speed sensor goes right to speedometer where 04-06 is processed through the ECM. Going to call Harley and see if they can flash the ECM to reflect my current configuration not sure if they can or I might have to find an ECM from 04-06. What are your thoughts?

    Thanks ~ Torch
     
  4. SilverFoXD

    SilverFoXD Active Member Contributor

    382
    28
    9
    Think you've got it. Mixing and matching electronics doesn't work like in the old days where we were dealing with just the electrics.
     
  5. torch947

    torch947 New Member

    3
    0
    0
    That's what it was wrong computer for the harness I was using , new computer once I got through the marrying sequence solved the issue.


    Thanks ~ Torch
     
  6. HDDon

    HDDon Experienced Member Contributor Retired Moderators

    5,456
    133
    196
    Thanks for getting back to us. I'm sure this will help another builder down the road.