It's on the side of the transmission, had 2 wires and looks like a little black cylinder.
The knock sesor is located, on your Isuzu 1290, at the front of the engine. The sensor screws into the engine. Wires connect the sensor to the senor light.
The speed sensor, on your Nissan, has a black cable. The speed sensor does not actually have any wires. The cable goes to the speedometer.
The coolant temperature sensor, on your 1999 Nissan, is located a few inches above the water pump. The sensor will have two wires going to it.
first of all, check all of your fuses. if that doesn't work, either replace the sensor on the transmission or the cluster in the dash. if that doesn't fix the problem, follow the wiring from the transmission all the way to the cluster, looking for breaks in the wires.
look down from the passenger front wheel toward the left its bolted to the transmission, usually gold in color, and has fat wires coming out of it.
On the top rear of the transmission is a wire connector with 2 wires. That's the speed sensor. On the top rear of the transmission is a wire connector with 2 wires. That's the speed sensor.
The knock sensor is located in the valley between the cylinder heads underneath the intake manifold. If you look in on the driver's side, it's the little black sensor with wires coming out. The connector for it is by the front cylinder head (follow the wires). They say you have to remove the whole $%^&ing intake manifold at a labor rate of 4 hours to get at it. I've found posts where people say they've gotten it out with extensions and u joints. Good luck, the dealer wants $900
Most knock sensors are located in the block on the firewall side. Should be the only sensor with two wires in the block. It will also have a camshaft position sensor as well. Hope that helps. I am not educated on Mazda engines.
disconnect the sensor from the wiring harness, removed the screw holding the sensor on, remove/replace and re-secure the screw and reconnect the wires.
Disconnect the battery. With the care safely raised, remove the two bolts holding the starter on. Disconnect the wires. Reverse the procedure to install the new starter.