2001 Grand AM GT Cooling Fan Running Constantly?

My 2001 Grand Am GT's cooling fan runs constantly. I'm guessing it's either the tempurature sending unit or the fan controller? It is kicking a code
"Engine running below normal tempurature". The car won't even warm up according to the tempurature gauge but it does throw heat. Any tips on what might be the problem?
Thanks
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On Sun, 31 Oct 2004 13:09:17 GMT, "Radyckle's News"

Yep, temperature sender (or the wiring to it) sounds most likely.
False cold readings would indicate an open circuit, rather than a short to ground.
Regards, Al.
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Ok thanks. What is the best way to trouble shoot for open circuit or bad sending unit? I know how to use a meter just not exactly sure what to look for.
Thanks
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The sending units on these are simply an NTC (negative temperature coefficient) thermistor. They are cheap enough that the easiest way to eliminate the sender is just to try a replacement. Or you can check the sender's resistance at a kniown temperature. If you want, you can substitute various resistance values for the sender to see if the wiring/PCM are OK. Some examples:
177 Ohms = 212 F 973 Ohms = 122 F 3520 Ohms = 68 F
(values are not exact, +/- 10 percent is fine)
Al.
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Thanks! I will try this
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my quick test is: Remove wiring and ground it. If the gage pegs hot, it's good. Plug the wires back in. Next measure the temp near the sensor (I use a Raytek infrared digital thermometer). If the temp is 200 and the gage says 100, replace sensor. GW
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Great! I will try this as well. Thanks for your input it's greatly appreciated.
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