I bought a 99 f-150 4x4 manual with the 4.2 engine when I bought it the speedometer and odometer didn't work and I ran the codes and came back with p0500 . The truck has rear abs only with no sensors in the wheels both transfer case and fear axle sensors are new . Today I tried to do a polarity test on the oss to where I believe I connects on the passenger side there are two large rectangular connectors . The top connector shows two wire of the same color and tracer when I couldn't find polarity there I checked all of them and found nothing . I can only trace the wires til they go behind the engine between the firewall . I would like to bypass them but first I need to make sure where they connect . I did check for polarity along the wire where I could by pushing a needle the wire with my meter connected the the oss plug I do get polarity where I can get to it I really need to know where the oss wires run to thanks

 

First, the rear ABS counts the ring gear teeth passing by it for speed.
There are no wheel sensors.
These sensors usually do not have a polarity because they 'generate' an AC signal voltage the PCM converts to digital signal pulses to be compatible with the program.
To test their outputs, raise the rear up on jack stands to be safe and run the drive line in gear.
Measure the sensor signal outputs with your meter set on the low AC scale.
You must do all this safely.
Without these speed signals the trans shifting up and down may not work correctly as well as no speedometer.
Good luck.

 

I'll verify I'm getting a single in the morning

 

truck is fixed . I found both wire's coming from the speed sensor on the transfer case were broke . I never did find out were but after running a jump to the pcm connector the od and speedo for the first time since I've owned the truck