I have an 84 2M4. Temp gauge stays on 100°F all the time. The only time the needle moves is when I start the car. It pegs as I start it and returns to 100.

All of the threads that say how to test it say there are two wires. One green and one green w/white stripe. Mine has one green and one orange.

I grounded out both wires. The green one pegged the needle when grounded and the orange did nothing. Not even the warning light.

Can someone please be kind and tell me what I am missing.

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2002 Audi Allroad. Tip. 100% Natural. (FOR SALE)
2011 VW Golf. (Wife's Wheels)
2002 VW Jetta (FOR SALE)
1984 Pontiac Fiero 4 speed Duke.

Perhaps you missed this in your search.....note the special instructions for 84s at the end of the article.

http://www.fierosails.com/tempgage.html

[This message has been edited by Gall757 (edited 08-06-2013).]

Thanks Gall. I didn't go all the way down. Too many words.

Anyway, I put a new sensor in and it works.

Now my question is, what is the preferred operating temp? I was hovering around 225°-235° traveling at 55 mph on country roads. Outside temp is around 70°

It seemed a bit high to me.

That's the high end of normal based on how the Pontiac engineers set up the sensors. The fan is supposed to come on at 235*, but the thermostat is supposed to be 195*. So normal operation is 200 to 230.

Then I have a problem.

My fan only comes on when the A/C is on.

The 84 has a 2 stage fan switch. I am not sure of the temps for each stage, but it is different than later Fieros. Sounds like yours is not working.

Lots of info here:

//www.fiero.nl/forum/A...110502-2-102588.html

[This message has been edited by Gall757 (edited 08-07-2013).]

Your problem may be only an inaccurate gage.

Check the temp that the ECM is seeing by using a scan tool to view ECM data.

Does the fan run off info from the gauge or the actual temp from ECM?

And what scan tool do I use? I am still fairly new to the Fiero world and still don't have a lot of items I need.

It has it's own switch.