Temperature gauge not reading. (Page 2/4)
luso31893 MAY 12, 06:57 PM
I did and the resistance was correct. the after market gauge I tried was one the previous owner had installed aswell at one point.
fierosound MAY 12, 07:49 PM
Wiring in an 84 is an "odd duck"...
Temp and oil idiot light are together. So ignore that for now.

Lets assume wiring is stock and the temp "fix" hasn't been done.
Gauge pegs when you ground the green wire. So wire and gauge appear to be right.

Maybe the wires are reversed in the connector to the temperature gauge sending unit.
Dark Green wire for the gauge should be going to the inner spade Thermistor.
TAN for the temp light should be on the spade closer to the open side.





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[This message has been edited by fierosound (edited 05-13-2020).]

fierosound MAY 14, 11:04 PM
luso31893 MAY 14, 11:20 PM
Okay. The sensor in mine both look like the one for the computer. Maybe that's the problem.
Gall757 MAY 15, 09:27 AM
Yes....that would be a problem. This is a common error at auto parts stores.

[This message has been edited by Gall757 (edited 05-15-2020).]

luso31893 MAY 15, 09:47 AM
Okay. I found one that looks like the stock one and got them to order it. Is that sensor also what tells the rad fan to start spinning? Currently I have it wired to a switch I have to flip for it to spin. Tested the stock relay and it seems fine but also can not find a replacement for it because it's the one with ac and all the spade terminals are in a line. Also has more than the non ac variant that I can buy.
luso31893 MAY 15, 09:49 AM
Oh wait I see the fan one in the pic now. I'll have a look at my engine after work today and see if I can find that one and how it looks. Who knows with the wiring mess the old owner did.
fierofool MAY 15, 10:23 AM
There are two independent circuits in the sending unit. One for the light and one for the gauge. One can be good and the other can be bad. Normally, the pointer sits on the bottom of the thermometer symbol with the ignition off. When the ignition is turned on, without starting, it moves to the 100 mark. If the plastic connector sheath has ever been replaced at the sending unit, it's possible that the wires were inserted in the wrong order. The solid green wire goes to the pin nearest the slot in the side of the sending unit.

[This message has been edited by fierofool (edited 05-15-2020).]

fierosound MAY 15, 10:55 AM

quote
Originally posted by luso31893:

Okay. The sensor in mine both look like the one for the computer. Maybe that's the problem.




quote
Originally posted by luso31893:

Okay. I found one that looks like the stock one and got them to order it.



Every month someone is asking about problems with the Temp Gauge.
And 99 out of 100 it's because the Parts Store gave them the Temp Sensor for ECM.
Then the parts guy says is a "newer style". NO it's the wrong part.

What they needed to ask for is the Temp SENDER for gauge and light.



That's why the previous owner couldn't make it work either and added an Aftermarket Temp Gauge.

You'll likely need a new pigtail connector for the new CORRECT Temp Sender you're getting for the Temp Gauge.
https://www.fierostore.com/...8&lp=88043&d=381&p=2

[This message has been edited by fierosound (edited 05-16-2020).]

fierosound MAY 15, 11:22 AM

quote
Originally posted by luso31893:

Is that sensor also what tells the rad fan to start spinning? Currently I have it wired to a switch I have to flip for it to spin. Tested the stock relay and it seems fine but also can not find a replacement for it because it's the one with ac and all the spade terminals are in a line. Also has more than the non ac variant that I can buy.



Only the 84 Fiero has a 2-speed fan arrangement.

When engine is running, radiator fan should be on at low speed.
It will come on at high speed when engine is over 225F or A/C is turned on.

Does the radiator fan come at high speed on when you have A/C on?
Then fan is working as it should and nothing wrong with the relay.


2-speed fan switches are discontinued and no longer available from anywhere.
Switch to a single wire fan switch like later Fiero models.

Radiator fan with not spin unless A/C is on or engine has reached 210F with Rodney's switch.
Get a 210F/200F fan switch and pigtail from Rodney to use with stock 195F thermostat.
http://rodneydickman.com/pr....php?products_id=235

[This message has been edited by fierosound (edited 05-15-2020).]