L3800 temperature guage

[312inchmagnum]

Trying to figure out why my Kubota L3800 temperature guage won’t work. Changed out my water temp sensor, cleaned and reattached connections to the back of the guage cluster, took clear cover off guage cluster and moved guage to make sure it wasn’t stuck. Not sure what else to try? Whenever I was changing out my tachometer cable I noticed this green wire was not attached to anything. I looked everywhere and did not find anywhere it could attach.

Whenever I turn the tractor on the guage will ever so slightly move up and that’s it.

Any recommendations on what to try next? Thanks.

 

[Flintknapper]

That is the Female side of a Bullet Terminal. Typically a solid green wire will be a ground wire of some sort.

Usually bullet terminals are used so that an item can be easily removed, inspected or replaced.

The Gauge itself ......who knows. If you have a wiring diagram for it....maybe when can help with some troubleshooting.

 

[GeoHorn]

When you turn the key “on”…the gauge gets power. It is looking for a “ground” via the sensor in the engine block. Try MOMENTARILY “grounding” the end at the sensor to see if the gauge suddenly swings toward “hot”. That will prove the gauge and wiring, and condemn the sensor.

 

[Jim L.]

The lead going to the coolant temperature sensor is a light green color. Possibly the loose lead is the one supposed to be going to the sensor?

The L3200, L3800 Workshop Manual, page 9-S29 has the information for troubleshooting. First I would check that loose light green lead.

 

[312inchmagnum]

The lead going to the coolant temperature sensor is a light green color. Possibly the loose lead is the one supposed to be going to the sensor?

The L3200, L3800 Workshop Manual, page 9-S29 has the information for troubleshooting. First I would check that loose light green lead.

the detached green lead won’t even reach over there…is there possibly more than 1 temp sensor on this machine or something?!?

 

[GeoHorn]

When I bought my tractor, the previous owner apparently had a mouse problem…which he repaired in an effort to cover-up the issue during the sale…by completely removing the wire. (Figured correctly a potential buyer wouldn’t run it long enough to be suspicious or look for a temp indication.)
When I opened up the instrument panel I found all kinds of such cover-ups I had to correct.
Anyway, it’s all good now due to close inspection of the electrical schematic and good quality wire. I suggest either marine or aviation grade wire for repairs instead of common hook-up wire sold at Autozone, etc. They are both designed for abusive environments and our tractors suffer that as well.
(Most marine and all aviation wire have the strands individually “tinned” before being twisted into a conductor (which prevents corrosion-losses) and the insulation of aviation wire is “tefzel” which is not appealing to chewing rodents.)

 

[Jim L.]

the detached green lead won’t even reach over there…is there possibly more than 1 temp sensor on this machine or something?!?

Referring to the posted photo and from that side of the tractor. Find the temperature sensor electrical tab at the rear of the engine and on top close to the heat shield for the fuel tank. That is what the green lead should connect on.

Not sure what other sensor you might have found. On the other side of the engine next to the starter there is a sensor but it connects to a short lead out of the wire harness next to the starter.

 

[312inchmagnum]

Okay I’m a moron so hopefully someone will learn from this. I found the water temp sensor. It was on top of the block close to the cab near the fuel tank. It was kind of “hiding”. Plugged it back in and worked fine. The sensor on the other side of the block is the oil sensor. Put the original one back in. Everything is working as should now. Thanks for all the tips.

 

[Jim L.]

Glad it got resolved. No worries.