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Discussion Starter #1
I went to run my 445 for a few minutes to keep it oiled up and the temp gauge went to full hot and stayed there until I turned the switch off. Does this indicate a short or ground in the sensor or an open sensor? It would seem to me that it thinks the engine is very hot or the sensor detects a hot temp. If it were open it wouldn't register anything? What do you think?
 

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The goofy temp sensor is probably to blame
 

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how long did it take for the gauge to get to max?.. seconds?... a minute or two"... or 10-15minutes?
 

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Discussion Starter #4 (Edited)
The gauge goes to beyond max hot in about three seconds. I finally found the test for the sensor in the manual. I don't like it! It says Unplugged the temp should read full cold. Grounded it should read full hot. Then it casually says, "If gauge not normal REPLACE the instrument panel! How about checking the sensor first?
 

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The gauge goes to beyond max hot in about three seconds. I finally found the test for the sensor in the manual. I don't like it! It says Unplugged the temp should read full cold. Grounded it should read full hot. Then it casually says, "If gauge not normal REPLACE the instrument panel! How about checking the sensor first?
right!... or the wiring!!
 

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Inspectorudy, Like it or not, too me, it sounds like the manual is correct!

If when gauge is unplugged and reads full cold, and when grounded reads full hot gauge/instrument panel is fine. If when unplugged gauge goes to full hot, BAD gauge!

Because it takes a few seconds to go full hot when connected, I'm thinking sending unit. I believe (??) the sending unit is a resistor that changes resistance with temperature and the gauge just reads the voltage/amperage (?) the sending unit allows to pass thru to the gauge. Bob
 

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The gauge goes to beyond max hot in about three seconds. I finally found the test for the sensor in the manual. I don't like it! It says Unplugged the temp should read full cold. Grounded it should read full hot. Then it casually says, "If gauge not normal REPLACE the instrument panel! How about checking the sensor first?
so did you test it?....

if you unplug the sensor, and then use a piece of wire to touch the sensor wire to engine / chassis ground, you should get the correct response as noted in the service manual.
However, if it goes full-hot after you unplug the wire off the sensor - regardless whether you just unplug it or touch it to groun, it could be a shorted wire to ground (wire insulation rubbed off against a metal part on the engine or chassis somewhere).... and not the instrument panel.....
At that point you want to either inspect/trace the full length of the wire.... or disconnect the wire off the meter itself in the panel, to see if things change.
If you disconnect wire at the panel itself, and it still goes full hot, with nothing connected - then indeed it could be the meter itself in the panel.
 

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Discussion Starter #8
I do not believe in coincidences but I just discovered one. Remember on my GX345 I had an issue where the 10 amp fuse would blow whenever I turned the key on after I had put on a new valve cover gasket.? It took ten fuses and a lot of fiddling to find out that the cause was the temp sensor wire had been captured under the valve cover inadvertently. This morning I went out to the 445 and found the temp sensor and followed it a few inches and guess what? The wire had been caught by the valve cover and had eventually worn through to cause a short/ground. The manual was right and it made me feel better about having done the exact same thing on the GX. The lady that owned the 445 always had the JD dealer do her work so that means that it has probably been done many times on these tractors since Kawa left no extra wire length in the area. The wire is almost stretched across the valve cover with no room to spare so if you remove the cover it is really easy to not notice the black wire that gets caught on the upper right-hand valve cap screw on the black plastic valve cover. Thanks for your comments.
 

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Inspectorudy, That's great...not that it was coincidental, but that you found the problem! It should also reaffirm your confidence in the service manual...wire/gauge was shorted and gauge read full hot. Bob
 
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