Speedometer and ABS light
I've got a 2000 Ranger 4x4 with a 3.0 V6. This past Saturday, we had a typical afternoon thunderstorm in central Florida. As I drove through this rain/storm, I noticed my ABS light flickering, and my speedometer guage bouncing; then it all went back to "normal". After about 30 seconds, it did the same thing, then back to normal (ABS light went out, and speedometer worked normally).
In doing some searching here and googling, I found that my year Ranger has an ABS/VCC sensor located on the rear axle. This sensor sends the "signal" to the PCM, who in turn controls the speedometer.
Could the heavy rain have gotten onto this sensor causing it to make the ABS light and speedometer react the way they did? I drove the truck Sunday in nice, hot sunny weather, and I had no symptoms as I did on Saturday.