One wire is positive, one negative and one is the sensor wire.

When on, I get 8 volts from positive to ground and 3.75 volts from sensor to ground with the sensor plugged into the speedometer head.

Spinning the hub there is no change in the sensor voltage.

The sensor read open on all three wires or millions of ohms.

So what do you think, is it a bad sensor?
Here is a couple links on testing them.
https://www.doityourself.com/stry/troubleshooting-a-vehicle-speed-sensor
https://www.speedwaymotors.com/the-toolbox/testing-2-and-3-wire-speed-sensors/28754

 

Spinning the hub there is no change in the sensor voltage.

Is that with the transmission in gear or in neutral?

 

In forward gear, ignition on.
In neutral does not change volts at speedometer. Just checked it.
Hub freewheels, it is an AWD setup, so easy to spin the hub fast.
Sensor just does not react to the spin of the hub.
Picture shows speedometer, 3 wire cable being measured sensor wire to ground.
Picture shows the sensor at the hub.

 

The magnet part of the sensor works.
I also took a fridge magnet and passed it in front of the sensor rapidly etc and got no change in output.

 

Apparently from the video test, there must be an internal pull up, as the power test just used the sensor and P.S., would seem to confirm a bad sensor!
Max.

 

Apparently from the video test, there must be an internal pull up, as the power test just used the sensor and P.S., would seem to confirm a bad sensor!
Max.

I hope so, sensor is a lot cheaper than the speedometer.
Inside the sensor is a lot circuitry.

 

Looks to be quite a bit of rust involved, many ABS hall sensors stop reading the hub teeth if the rust is too heavy.

 

I will look into that, but I think it is a flat disc with drilled holes that pass the sensor.
The photo shows an inline view with the entire disc surface, so it looks rustier than it is.

 

I ordered a cable off ebay used, got it and speedometer works again.

I had checked everything and seemed to point to the sensor as bad and it was.

The speedometer when off reads about 2 mph, cant fix that really unless I remove the cover.

http://ka7oei.blogspot.com/2013/10/repair-of-speedometer-on-polaris.html

Here he says you can actually repair them.

 

I ordered a cable off ebay used, got it and speedometer works again.

I had checked everything and seemed to point to the sensor as bad and it was.

I'm confused by that pair of statements.

So, you replaced the cable and now it works, indicating bad cable?

Or, you checked everything and determined that the sensor was bad?

Was it the sensor or the cable? Regardless, I'm glad to hear you've got it working. Nice job!

 

I'm confused by that pair of statements.

So, you replaced the cable and now it works, indicating bad cable?

Or, you checked everything and determined that the sensor was bad?

Was it the sensor or the cable? Regardless, I'm glad to hear you've got it working. Nice job!

The sensor is formed onto the cable end. So all is replaced. Has a plug that fits into the speedometer.

 

When I saw speedometer cable I was thinking the old moving cable in a sheath.