hey guys have a 00 f-350 here with a 7.3 diesel. the sppedometer is not working, the o/d light flashes. have code p0500. i have replaced the diff sensor and pigtail and still does not work.any ideas??? i hook up my scanner and go for a drive and have no mph signal through the scanner. now my understanding is this is not like most cars where the speed signal comes from the output sensor on the tailshaft of the trans, but rather the cluster gets the signal from the diff sensor which sends a signal to the abs module which then sends a sig to the bcm and then finally to the cluster. am i wrong in how this works and has anyone ran into this before???

 

no your not wrong my truck did the same thing but i got lucky with just the senor in the diff does your truck have a fuse for it if does check that it may have blown and does the rest of your dash work?