Was the Speedo working prior to installing the sensors ? For a while I ran only 2 front sensors and the rears I cut out. My Speedo still worked. Till magically it stopped after messing with the wheel bearings. The Speedo runs of ABS as we now. There is a crown type metal ring that the sensors read. Maybe that is messed up or rusty or something ? Anyways, I gave up and installed a Tacoma speed sensor. Which is a sensor in the back of the tcase. But you need to run 3 wires , one goes to the cluster.