Temperature guage reads fully warm

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TriggerFish
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Post Sun Aug 14, 2016 9:35 pm

Hi all,

I have an intermittent (but largely present) problem with my temperature gauge whereby it reads fully hot all the time. I've tightned the brass nut.

Following the test in the wiki, if I disconnect the brown plug, the gauge drops to the off position. If I short the sensor to ground, it jumps to hot again (ruling out the wiring?). In my mind, it's a failure of the sensor.

Anything else I can test before I replace the sensor?

Cheers,
Joe
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Brianmoooore
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Post Sun Aug 14, 2016 9:51 pm

It seems likely that your diagnosis is correct, but if you want another test, measure the resistance of the sensor from its single pin to its outer casing, hot and cold.
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TriggerFish
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Post Mon Aug 15, 2016 8:54 am

Thanks - I'll do that first before ordering one. I'll pop it in a pan of hot water after work and see what it reads. I can test the suspect thermostat at the same time.

Cheers, as ever, Brian!
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Brianmoooore
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Post Mon Aug 15, 2016 9:50 am

Just pull the plug off and test it in situ. As ever, one of the most important rules in diagnostic testing is to disturb as little as possible before the culprit is nailed.
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TriggerFish
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Post Mon Aug 15, 2016 6:07 pm

Good point. I was reluctant to start it for fear of overheating, but issue solved as I remebered I had a spare brown plug at my unit. I made sure the problem was present, swapped the plug into the other sensor and the gauge dropped, so I swapped the sensors over.

Now, to rule out if it actually is overheating, or if it's just paranoia from a progressively degrading gauge...