Installed a new head unit in my 08 GT today, and after putting everything back together, i very quickly realized that neither my speedometer or odometer worked any more. I proceeded to pull the center plate and head unit back out just to check if i had screwed up a harness in the process and found nothing. Now I changed the head unit in my 04 tibby several times, and have had this particular unit in it for the past couple years with no problems. Ive been racking my brain (and google) all afternoon trying to figure out whether somehow the head unit swapped caused the failure or if it was sheer dumb luck that it happened at the same time. So, if anyone has any insight into this, it would be GREATLY appreciated.