TC-35D Temperature Guage

[felixedo]

My TC-35D is not registering any temperature on the panel guage. I went ahead and replacd both the thermostadt and temperature sending unit. Is there a way to test the guage itself, to see if it's working?

[JC-jetro]

Try to short out the sending unit cable to ground, while the key is in "on" position and then observe the gauge.Report back with your finding.

JC,

[jinman]

+1, What JC said. . . Remove the wire from the sending unit and ground it. That's the easiest point. While grounded, your gage should go to the maximum reading. Any less means you need a new gage. The instrument panel comes apart and the gage is replaceable. Go to this thread to see photos and description.

[pedalstomper78]

jinman......same thing on the fuel gauge?

[jinman]

jinman......same thing on the fuel gauge?

Yep, and the tach also is replaceable. The hour meter, though, is soldered in and not a replaceable part.

[JC-jetro]

Excellent read Jim could not have expected any less

Go to this thread to see photos and description.

[felixedo]

Thanks for the instructions. This may be a drawn out conversation because it's a long way from the internet to the tractor. OK, I grounded out the wire, but did not detach from the sending unit. (just jumped to the ground) So, do I need to redo the test? Anyway, no response from the guage. So, If the test is reliable as I perfomed it, I assume either the guage is bad, or there is a break in the wire.

[JC-jetro]

The purpose of grounding the wire is not to test the sender unit. It is intended to test the temp gauge, so your test is accurate and shows your temp gauge is not responding that could be gauge itself or wiring to it. I follow the sender wire toward the cluster and try to short it out to chassis closer to cluster. You mighty be able to find an open. if you can not find an open all the way to the cluster then you need to do what Jim has done to isolate the source which most likely going to be your temp gauge. I'm sure Jim will be back with guidance soon.

JC,

Any reason for not taking the wire off the sending unit and have it grounded? just curious.

Thanks for the instructions. This may be a drawn out conversation because it's a long way from the internet to the tractor. OK, I grounded out the wire, but did not detach from the sending unit. (just jumped to the ground) So, do I need to redo the test? Anyway, no response from the guage. So, If the test is reliable as I perfomed it, I assume either the guage is bad, or there is a break in the wire.

[jinman]

Any reason for not taking the wire off the sending unit and have it grounded? just curious.

JC, I think the reason is that the wire coming to the sending unit is a female spade connector. The sender has a male tang. It's fairly easy to slide the female spade off just a bit so you can get an alligator clip on the male tang and then attach it to ground.

The schematic shows the wire running straight to the instrument panel without going through any connectors. It enters the instrument panel at pin #15 of the connector. It's a brown wire, but there are many brown wires going into that connector. If the connection looks clean, I don't think I'd spend a lot of time investigating a broken wire. The problems with the temperature gage are so common that I think felixedo has sufficiently isolated the problem already. My best bet is it's a stuck or malfunctioning gage.

[JC-jetro]

JC, I think the reason is that the wire coming to the sending unit is a female spade connector. The sender has a male tang. It's fairly easy to slide the female spade off just a bit so you can get an alligator clip on the male tang and then attach it to ground.

Jim,

What you said is exactly how I saw it on several tractors including my Ford and Kubota. Pulling the female spade connector off and putting it back in would just takes a few seconds and was curious why the OP elected not to pull the connector off, use a paper clip and short it out. I have made short pieces of wire that I crimped male tang on them just for test like such. At any rate I also think he has the answer already. As you said if the wire directly lands on PIN#15 then I would not spent toot much time on it , see it hard for it to break in the middle. So I take it this circuit is not protected by any fuse as it only senses resistance change. He might be able to find some obstruction for the needle. Your pics could not me more clear to take the cluster off and get her done.

JC,