Cat 306

[pittedmess]

4M40 engine. Need normal ohm range for coolant temp sensor Gauge won’t register. Coolant temp good
Thanks

 

[ahart]

Let’s back up and get a machine serial number first. After that, information becomes easy to source.

 

[pittedmess]

MXH00487

 

[Cmark]

No information available on SIS regarding the ohm range of the sensor unfortunately.

It appears to be a simple one-wire sensor. Quick and dirty test - Ground the sensor wire. If the gauge goes to max then the sensor is faulty.

 

[pittedmess]

Concerned about doing that, not knowing the configuration of the gauge cluster C Board Know that works, but thought I would ask before I cause more issues. Not knowing if I have a neg. or positive coefficient is troublesome. Seems to read positive C

 

[Nige]

It’s actually a sender rather than a sensor which makes the circuit it feeds much more simple. You’ll be fine to simply pull the wire off the sender and ground it, to the engine block, then observe the reaction of the temp gauge.

 

[pittedmess]

Ok. Grounded it. Gauge pegged all the way up. I don’t like to just ground wires without some input from those of you that can give me direction. Ordered service manual. Deere has all the values assigned in their manuals. Hope Cat does the same. Never did throw parts at things when knowledge overrides poor decisions
Thats to everyone for their help in making my decision to ground it

 

[Nige]

Ordered service manual.

Where from.? Not something on a memory stick from Eastern Europe.? I hope you are aware that a genuine factory service manual retails at $1000 new.

BTW the replacement sender is Part Number is 190-5769.

Deere has all the values assigned in their manuals. Hope Cat does the same.

If we can't find anything in the online system then there will be nothing in a service manual because the service manuals are nothing more than an agglomeration of the documents that are available online.

The electrical schematic (which will be included in a genuine service manual) has specifications for a large number of solenoids and senders/sensors but not the coolant temperature sender unfortunately.

 

[pittedmess]

Just want schematics. Nothing fancy The rest is intuitive for ole farmers. If we had to depend on factory service. We’d go broke

 

[Nige]

Just want schematics.

So why buy a service manual.? All you had to do was ask. Check your messages.

 

[pittedmess]

Thank you. Never thought about you folks. Lesson learned

 

[pittedmess]

Wanted to let you guys know what I found when I researched the wiring diagram. The temp sensor was bad, however it was burned out[cut it apart with parting tool on lathe]. Come to find out the converter [24 to 12] was bad. I hope this didn’t wreck anything else cause there was 24v on one pin that should have been 12. Cat may be too high so I will go to a marine supply and put new Molex connectors on it. Easy with the wiring info
Thanks Nige