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Re: AUXILIARY FAN ALWAYS ACTIVATED
The fan should be controlled by engine temperature, and go on when it reaches a certain point. If it's on all the time (even when engine is cold) the 'radiator fan switch' may be stuck in the closed position, which completes an electric circuit and turns on the fan on. Check the switch. countrycurt0
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How do you know head pressure is high? Do you have an auxiliary electric cooling fan that is not coming on in this situation? It should be in front of the AC condensing coil. There may be a switch tied to the system that is bad. This switch is sometimes activated by the pressure in the high-pressure line to the condenser coil. If there is not enough freon (134a) the pressure will not be high enough to activate the cooling fan switch. I recently added one can to my system and it made the fan run whereas it did not before adding the freon.
It's most likely a bad left front wheel bearing or possible tire noise, switch the left front tire with the rear tire and see if the noise changes. If not have the wheel bearing checked, it may need to be replaced.
My suspicion is that the fans may be coming on but they are not picking up speed when you turn on the A/C. Your car would have some of relay to control the speed of the fan whenever the A/C was turned on. This relay system would also increase the speed at which the fans run when the engine heat turns them on too.
Try starting the car cold and turning on the A/C right. Even though the engine is cold the rad fan should start up when you switch on the A/C. Once the engine gets hot the fan speed should increase accordingly when you switch on the A/C.
I'm not familiar with how Chrysler makes this work so I'm unsure what to repair but this is most likely your problem. Hope this helps.
REPLACE THERMOSTAT AND RADIATOR PRESSURE CAP.CHECK MECHANICAL COOLING FAN.SHOULD HAVE RESISTANCE WHEN TURN WITH HAND.IF FREEWHEELS FAN CLUTCH NEED TO BE REPLACED.CHECK TO MAKE SURE AUXILIARY ELECTRIC COOLING FAN RUNNING HOT WIRE COOLING FAN IF FAN RUNS.YOU HAVE FAULTY THERMO SWITCH LOCATED AT THE BOTTOM OF RADIATOR ON THE LEFT HAND SIDE ON 4 CYLINDER ENGINE FOR V6 ENGINE THERMO SWITCH LOCATED ON THE LOWER RADIATOR HOSE ON THE RIGHT HAND SIDE OF THE ENGINE COMPARTMENT. CHECK FOR BLOWN COOLANT FAN FUSE OR FAULTY RELAY.IF THE AUXILIARY ELECTRIC FAN DONT RUN WHEN HOT WIRED THE ELECTRIC FAN FAULTY.
The auxillary fan is used for AC cooling purposes, and your vehicle
under normal circumstances should not overheat regardless of the status of the auxillary fan.
That being said, the auxillary fan is controlled by the PCM based on AC switch position via a fan
control relay in your fuse box under the hood. There is no fan switch
for it, as it is turned on based on PCM observance of AC control switch position.
Some things to look at regarding your overheat condition:
When the vehicle begins overheating, what are the conditions of the radiator hoses? Are both firm, or only one and the other soft? Are both hot, or is one hot and the other only warm?
Both a failed waterpump and a failed shut thermostat will show a hot hose on one side and only a warm hose on the other side of the radiator.
A failed (stuck shut) thermostat will also result in one very firm hose (highly pressurized and nowhere to go with the thermostat shut) and one relatively soft hose.
You can take the radiator cap off (BEFORE it pressurizes) and watch the water level as the car runs. If the thermostat is opening and waterpump is pumping, you will see fluid flow once it gets to operating temperature.
Watch your engine fan and see if it is engaged or just spinning freely. When warm and the engine shut off, the fan clutch should be engaged making the fan more resistant to turn. If it spins freely, the clutch is failing.
Check the area around the radiator and between it and the condenser for obstructions to airflow.
Obviously check the condition of the coolant for heavy scale/sludge. The 3.0/3.5 engines are notorious for turning coolant into thick rusty puddy.
Is the starter turning over the engine when it wont start or is nothing happening at all?
I might have your solution if I have more details.
If the engine is turning over but not starting then switch on the ignition and push it to start.If it starts you probably need a new ignition switch.
You may need to replace the thermostat. The thermostat is what controls the fan coming on. If the car is having an overheating problem the check engine light will be on since it is not operating in the allowed tollerances.