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Discussion Starter #1 (Edited)
My engine will go all the way to hot without the fans ever turning on. As long as I have the A.C. on I have no problems in any conditions. But sometimes its nice outside or even on the cool side or at night. Sometimes I don't want to run the air so its really inconvenient. :hmm: 1999 Eldorado 4.6 ESC
 

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98 eldo/KD54 w/N37,T96,QA1,D55,DS3,U1Z. U3R next
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Faulty cooling fan sensor/switch.
Faulty cooling fan relay.

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Coolant sensor wiring broken/ sensor disconnected
 

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1997 Seville STS, 2000 Seville STS
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If the coolant sensor was bad, then the quage in the car would not display any information or the incorrect temperature, there is only one sensor in the car, and it provides the info to the PCM/IPM that controls both the fan turn on temperatur and the guage in the dash.
 

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2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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Go down to Engines, Northstar Performance and read the sticky thread titled something like "temperatures and cooling fan operation explained". That should give enough background to make a better diagnosis.
 

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White Diamond '03 DHS (with DTS floor shift)
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The fans not coming on may not be your biggest problem if the engine is actually overheating as indicated. You might want to figure out if that is just an indication problem or not before worrying about the fans.
 

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98 eldo/KD54 w/N37,T96,QA1,D55,DS3,U1Z. U3R next
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2,125 Posts
Here's the circuit,

Again faulty relays, bad switch, worst case bad pcm. The fans come on when the a/c circuit is commanded.

That weeds out the fans, the wiring.

What's left is what is doing the controlling without the a/c being commanded.
 
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