Long story here but I'm still hoping for a simple explanantion. I started having Speedometer/odometer problems after a power surge when my alternator went out. I knew the alternator was going bad and I tried to limp home another 5 miles rather than pay a tow bill and the alternator overcharged for a few seconds before completely dying. Since that time the only problem I am left with is my Speedometer and odometer have not worked. Scan tool says p0500 and I have repleced the ABS sensor on the differential with an OEM part but still no speedo or odo. I have checked all the fuses and relays associated multiple times. I do suspect that the RABS resistor is bad but there is no ABS light and it doesn't make sense that this one resisitor is the sle key for the whole speed control circuit. It's a manual transmission and RABS only. I swapped out the Cruise Control Servo with no luck as well. I am running out of options before having to take it to a dealer because I have to pass inspection. I have also checked and there is no power coming to 679 (GY/BK) into the instrument panel. I have also checked continuity for the rear harness to the ABS sensor and it is good. I know I rambled a lot there but any ideas or suggestions would be helpful at this point.

 

Some years also have a speed sensor in the trans, where the speedo cable used to go. I believe this is where the speedo gets it's signal from on models that use this type sensor.

 

98-00 only use the ABS sensor on differential.