Temp sender troubleshooting

[Laneman950]

Now that my starter is working I'm moving on to the idiot lights. All three bulbs were burned out so I put in new ones. Now 2 work, oil and charge. The temp light does not light when the key is on. I get no voltage to the light. When I remove the wire from the sender and touch it to a good ground the light works. Anyone know how to test the sender? Put it in boiling water and take a reading would be my guess.

Anyone ever do a conversion to real gauges? If so, how and which brands?

 

[cp1969]

The way you have described it, the temp light should probably NOT light when the key is turned on. The other two (oil and gen) are telling you the truth--there is no oil pressure, and there is no charge, so they light. But so is the temp gage--the engine is not hot, so it doesn't light.

Heating the temp sending unit will answer your question about whether or not it will close the circuit.

Maybe I didn't understand your question correctly.

 

[Laneman950]

I'm researching how the water temp sender works right now. I would think you would want it to light when the key is on so you know the idiot light bulb is not burned out. The only test I've found so far is do a resistance test at the sender. There should be some higher resistance when cold. If I had the specs for the sender I could test when the engine is hot and compare. I just want to know that it works in case I overheat. Would much rather have a real gauge or both. The best thing would be a screaming horn when it gets hot. I think they make those for boat engines.

 

[cp1969]

You would want it to come on when the key is turned, to test the bulb, but then go out--because the engine is not hot at that point. That would require a level of circuit sophistication that your tractor(?) probably does not have.

In lieu of that, you could wire in your own press-to-test circuit which will test the bulb but nothing else.