nissan pickup speed sensor

I have some recent experience regarding speedometers/speed sensors. Unless your situation is unusual, I think your problem is in the speedometer head - not the sensor.

FWIW, on my '94 pathfinder, the sensor is located on the bottom of the transmission, on the passenger side. There are a few sensors there. The speed sensor one was the closest to the front of the vehicle. In my case, a new sensor was $60 but I found one at a junk yard for $30. Replacing it didn't solve the problem. I traced the problem to a bad IC in the speedometer head. Unfortunately, this IC is not available.

If this matches your situation, you might want to check junkyards or Ebay for a new speedometer head. However, be careful as the speedometer head is a weakness of Nissans of this vintage. In my case, I was able to implement a replacement circuit for the defective IC.

Marko