Testing a 3 wire speed hall effect speedometer sensor for a Polaris ATV, it seems a bad sensor

Thread Starter

sdowney717

Joined Jul 18, 2012
648
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
 

Thread Starter

sdowney717

Joined Jul 18, 2012
648
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.
 

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MaxHeadRoom

Joined Jul 18, 2013
21,623
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.
 

Thread Starter

sdowney717

Joined Jul 18, 2012
648
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.
 

ebeowulf17

Joined Aug 12, 2014
3,274
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!
 

Thread Starter

sdowney717

Joined Jul 18, 2012
648
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.
 
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