overheat / check engine light on

2004 PONTIAC GRAND PRIX
130,000 MILES • 6 CYL • FWD • AUTOMATIC
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CUSTOMC5757
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my 2004 grand prix, 3.8 vin2 cooling fans work when i open the circuit, but will not come on when engaging ac or when the temp rises in normal operating scenario. Changed thermostat, temp sensor, relays and checked wiring form sensor to harness? Seems ok? But still not coming on
Aug 10, 2011 at 11:02 AM
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WRENCHTECH
  • ✓Experienced Mechanic
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How hot will the car get in degrees?
Aug 10, 2011 at 12:10 PM
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WRENCHTECH
  • ✓Experienced Mechanic
  • 20,760 POSTS
Also, have the codes read and post them here.
Aug 10, 2011 at 12:10 PM
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CUSTOMC5757
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  • 2 POSTS
The temp gauge will rise to above 3/4 mark if I allow it too. The only code that has surfaced is PO118. Thanks
Aug 10, 2011 at 8:17 PM
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WRENCHTECH
  • ✓Experienced Mechanic
  • 20,760 POSTS
I suspect you're getting the PO118 because you are unplugging the temp sensor with the key on. It might not be a bad idea to change it anyway if you don't have a scan tool to read the actual data live. We see this question often and most of the time there is actually no problem at all. The fans are not even programmed to come on until around 225degrees or higher intentionally. That's pretty high on the gauge but is normal.
Aug 11, 2011 at 2:54 AM
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