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There is a connector under the driver seat that sometimes corrodes from water intrusion.
The VSS wires go through it.
Would also help if you filled out a signature with the details of your truck.
99 is not enough to go by in this case. 4wd will have 4WABS, which operates the speedo signal differently than a 2wd/RABS.
4WABS, the VSS signal is conditioned by the 4WABS Module, then sent to cluster, PCM, GEM and Cruise.
RABS, the VSS signal is sent to the GEM, conditioned and sent to cluster, PCM and Cruise.
The only thing common with wipers and VSS is the GEM, RABS only.
4WABS has a VSS input to the GEM labelled speed dependant wipers, which I believe is the mechanism that cancels Cruise when wipers are on (High?).
There is also a tone ring on the large gear inside the axle pumpkin. If that ring is broken, you won't have a VSS signal. You might also reinstall the newer VSS, since it is depth sensitive. If the gap is too large, no signal results.
While it's out, look for damage as if the tone ring had hit it. Might also ohm it out. It should be 1400 ohms. While you have the VOM out, install the VSS, jack one side up and spin that wheel. Using the mV scale, see how well it pulses. Investigate the wiring if all that checks out.
