Oil temperature gauge - reading depend on voltage

[MOTOMYSZOR]

I have installed mu oil temperature meter from some time ago but just few days ago I noticed that something is wrong.

when I was waitng on traffic light with indicator on, I noticed that temperature jumps up and down 5-7 Celsius..... nothing major.

But today when I switched lights on, temperature reading jumped 15-17 degrees up.... when I push brake lever, it adds another few degrees.....

I don't care for extra accurate read during ride, but in traffic I would like to know if oil temperature is still 110C or already close to 130C......

I have digital meter with single wire probe and I am wonder if voltage fluctuations in system affects electronic in gauge or probe replace will sort my problem....

I am not good with electric and electronic so maybe You have any idea what to do....

[Bones]

Sounds like you have a faulty gauge, I had similar problems when I had a digital gauge fitted where it was fine at first, but then would read temps all over the place. I think the problem is a lot of these gauges aren't waterproof so water gets in and after a while upsets the electronics in them. I threw my digital one away and fitted an analogue style one with a stepper motor fitted. Works well, is accurate, and can even change colour of the face.

[Pat Conlon]

As an experiment, you could try powering it directly off the battery....see if it settles down.
Perhaps voltage drop thru your harness is the issue.
If the battery voltage works, then you could put in a simple spst relay to power the gauge off the battery. Control the relay coil with power from your key switch.

[MOTOMYSZOR]

As an experiment, you could try powering it directly off the battery....see if it settles down.
Perhaps voltage drop thru your harness is the issue.
If the battery voltage works, then you could put in a simple spst relay to power the gauge off the battery. Control the relay coil with power from your key switch.

And that how it is powered - directly from battery through relay.

I will start with probe.... I will replace it.