Help with a temp gauge please!

[lristau 01]

Hey guys thanks in advanced, here is my issue.

Tractor is a bobcat CT122

My temp gauge sits at zero. I have replaced the temp sender with a new one and it didn't resolve the issue. If I ground out the white wire with a black stripe the gauge goes to max hot.

When I reverse the white wire with black with the white wire with red the gauge will go to operating Temp and just stay there. When it's wired this way I can heat the sensor up and the gauge will go up and then cool back down to operating Temp but it stays there even after cooling down.

The white wire with back shows roughly 10 volts and the white with red shows 5 volts.

When I take the black ground wire off and touch it to the white wire with black it makes the gauge go max hot as well. So I am assuming the ground is working?

I hope this makes sense. I am leaning towards some kind of computer issue or relay? but have no clue.
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[Dave M7040]

Seeing you have three wires on the temp sensor makes me think it is a more sophisticated system.

Read the attached link.

3 Wire RTD Sensor| Wiring a 3 Wire RTD | 3 Wire RTD Probe

3 Wire RTD Description
In order to minimize the effects of the lead resistances, a three-wire configuration can be used. ... There is a lead resistance in each arm of the bridge so that the resistance is cancelled out, so long as the two lead resistances are accurately the same.

I know this does not help you but rather shows you it may not be simple.

Dave M7040

 

[Oaktree]

Not familiar with the Bobcat tractor, but my snowmobile has a 3 wire temp sensor in it...it's actually 2 sensors in one. One is a straight circuit to the gauge, the other goes to the ECM so it can do its thing.
Without a schematic, it's just guessing about how it's wired.

 

[lristau 01]

Here is the schematic. I screen shot both sides so hopefully you can read them better

 

[lristau 01]

After looking at these drawings. I am curious now if the black/red wire from the gauge itself is loose or broken. Would that make sense? If that ground wasn't working then the gauge would just sit at zero right?.