Radiator cooling fans run constantly with engine running

Asked by johnwp53 Dec 27, 2009 at 12:01 AM about the 2000 Dodge Intrepid FWD

Question type: Maintenance & Repair

Both fans run at high speed constantly when the engine is running - even with the A/C off. No problem codes stored and the MIL is off.

If I disconnect the A/C pressure transducer the fans stop and cut in at low speed when the engine coolant temperature reaches 216 degress.

I swapped out the A/C pressure transducer with a known good one from one of my other intrepids but no change. High-side Pressure in A/C system is 100 psi with A/C off.

With the ignition on and engine not running, at the A/C pressure sensor harness connector, the supply voltage is 5.1 volts and the A/C pressure signal is 4.7 volts. The resistance in the ground wire to the PCM is 1.4 ohms so no problem there.

Anyone experienced this problem before or have any ideas what the cause might be?

chucks answered 13 years ago

I have the same problem with my 07 caravan....., were you able to sovle it..., and if so, what was the cause? thanks chuck

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William answered 13 years ago

I had the same problem in a 2001 and it was cause the thermostat was stuck open. Since around the 2000 model year cars have come with failsafe thermostats. So when they stick, they stick wide open. This throws the vehicles computer into what is termed "hyper cool" and runs everything wide open to protect the engine as much as possible.

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