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Chrysler Repair/Air conditioning: fans not activated


QUESTION: 2007 dodge grand caravan SE 3.3L. When A/C switched on the clutch engages but condenser/radiator fans do not come on.  I noticed that the fans do turn on when engine is the running and the temp gauge reaches about half way. My observation was without the A/C turned on. Please help!

ANSWER: Hi Tony,
As best I can tell, the fans don't come on automatically when you select AC. Rather the factors that determine the fan action are the AC pressure transducer reading, the coolant temp sensor, and the ambient temp sensor,  It may be the case that the specific operating conditions are not combining to 'call' for ran operation. I would not be concerned unless this is causing the overheating of the engine coolant.
Please read the PS (below) and respond to it.

---------- FOLLOW-UP ----------

QUESTION: Thank you for getting back to me. Maybe I should have mentioned that I hooked up a gauge to the A/C system and the high side reading was above normal. I mean above 300psi and A/C will not blow cool air unless I cool the condenser with water to get the pressure to drop down to 100-150psi.

Thank you

Hi Tony,
That sounds like the pressure is being 'seen' by the transducer as too high, which then causes the PCM to lock out the activation of the compressor clutch until it drops to an acceptable level. Is your system perhaps overcharged with refrigerant?
A fault code readout may also reveal a malfunction in the system so try that: ignition key "on-off-on-off-on and leave on" doing that is 5 seconds or less elapsed time. Then watch to odometer window to see if the mileage reading is replaced by a 4-digit number preceded by a P. If that doesn't work a plug in code reader may be needed. Some nationwide auto parts stores will do that for free (e.g. Autozone).
I would appreciate your rating my answers and considering giving a "yes" answer where you see the question about a nomination of me for 'volunteer of the month'. Thanks.

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Roland Finston


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