Hello, This is my first post here.

I have had trouble with my speed sensor for several months. The check gauges light would come on & the tach, odometer, speedometer, and lights on the gear indicator would not work. After unplugging the wire connector from the sensor, cleaning it & and putting some silicone around the edge it would work.

That finally got to where it wouldn't prevent the trouble so I replaced the sensor and wire connector today and still have the problem. Does polarity matter on these two wires? If that's not the problem, what else could cause these kinds of issues. Also, when this happens the pickup is very sluggish when starting out but improves after about 20-30 mph.

 

Polarity would matter, you have a signal and a source going to a sensor.

 

i dont know if the polarity of the wires would matter all that much as ths is a voltage generating sensor. It makes an A/C voltage that the computer converts to D/C analog to operate the speedometer. Jack the truck up and run it in gear. Use a A/C meter and check the output of the speed sensor. If it makes voltage, check it futher up the wires, it could be broken up the line somewhere.