Temp. Guage

[fiatfanatic]

What's up everyone! My temp.guage is not working!! It's getting power at the guage, but niether wire at the sensor is getting power. I'm not sure if the wires at the sensor are supposed to be hot or if they just send a signal. Any ideas? Thanks in advance!!!

[pauljdav]

I believe the sensors simply ground the wire from the gauge.

Try grounding the with that goes to the sensor from the gauge. If you still have no movement on the gauge, then you either have a bad wire from the gauge (broken somewhere in the path) or the gauge itself may be bad.

Paul

[fiatfanatic]

Thanks for the response! I tried grounding the wire but got nothing, so I guess it's time to get a new guage! Thanks again for you're help!

[fiatfanatic]

One thing I noticed is when I disconnected the wires from the sensor the engine died. Why does it do this? Thanks!!!

[pope]

On a fuel injected car, every thing leads back to the computer (ECU). Engine temp is important for the ECU to know.

[fiatfanatic]

Gotcha! Thanks!!

[bradartigue]

I'm sure I'm posting way too late, but the sensor for the temperature gauge is not the same as the sensor for the fuel injection computer.

The FI sensor, in the forward part of the coolant "T" near the radiator, will kill the engine if disconnected. It has nothing to do with the gauge on your dashboard.

The gauge on the dash is controlled by two sensors in the middle of the cylinder head; one turns on the idiot light if the temp reaches about 240 degrees, the other is variable and runs the gauge itself.

[fiatfanatic]

I'm sure I'm posting way too late, but the sensor for the temperature gauge is not the same as the sensor for the fuel injection computer.

The FI sensor, in the forward part of the coolant "T" near the radiator, will kill the engine if disconnected. It has nothing to do with the gauge on your dashboard.

The gauge on the dash is controlled by two sensors in the middle of the cylinder head; one turns on the idiot light if the temp reaches about 240 degrees, the other is variable and runs the gauge itself.

Wow! This post changes everything! I can't tell you how thankful I am that you posted! I thought that the temp. sensor was the one on the water neck! Can you tell me which one is which? An is there a way to test them? Thanks!

[pope]

Brad is the man who knows all about electrical.
In the mean time, some food for thought. On the top of the engine, between the sparkplugs there are two water temp switches. They have 2" black rubber caps on then. They and the wires are probably very hard and brittle. The wires that feeds them are covered in a green plastic covering. The individual wires are gray with black stripe and a green with a white stripe. Those are the temp sensor wires. The gray/black is the warning light and the green/white is the gauge needle wire. Check these wires closely as they are in a very hot area and can dry out and crack easily. I believe they are ground wires as there will be no power going through them. They work on ground resistance.
I also think that you should be able to ground the wires to the body and check for condition.
The gray/black wire should be the one closest to the front of the car and green/white closest to the firewall.
Try grounding the plugs first and check for wire condition. If that doesnt work I am sure Brad can help you further.
The small square modular plug you kept removing before was the ECU temp gauge.

[fiatfanatic]

Brad is the man who knows all about electrical.
In the mean time, some food for thought. On the top of the engine, between the sparkplugs there are two water temp switches. They have 2" black rubber caps on then. They and the wires are probably very hard and brittle. The wires that feeds them are covered in a green plastic covering. The individual wires are gray with black stripe and a green with a white stripe. Those are the temp sensor wires. The gray/black is the warning light and the green/white is the gauge needle wire. Check these wires closely as they are in a very hot area and can dry out and crack easily. I believe they are ground wires as there will be no power going through them. They work on ground resistance.
I also think that you should be able to ground the wires to the body and check for condition.
The gray/black wire should be the one closest to the front of the car and green/white closest to the firewall.
Try grounding the plugs first and check for wire condition. If that doesnt work I am sure Brad can help you further.
The small square modular plug you kept removing before was the ECU temp gauge.

Damn you guys are good! I will try grounding them today and see where that gets me! Thanks again for all the help!

[fiatfanatic]

Okay. I tried grounding them and got nothing. I also got my wire tester out to check if both of the wires were grounded and they are. Could the guage be bad?

[pope]

You did have the ignition in the ON position while testing, right?

[fiatfanatic]

Yes! I actualy had it running. I even tried swapping out the sender with another one I had laying around from the old engine.

[pope]

I then think its your gauge.

[fiatfanatic]

I then think its your gauge.

First of all, thanks for all of your help with this! I wouldn't have gotten as far as I have without everyone's help! I went ahead and ordered a new gauge! I have one more question though. What sends the signal to the electric fan? I had it running for a about ten minutes the other day and it never came on. Here's the kicker though, when I jumped the wire (and them immediately removed the wire from the source) it came on and stayed on until it needed to go off. Then it didn't come on again until I did the same thing all over again.