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Old 05-16-2014, 06:47 PM
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04WJ Air Conditioner Issues

'04WJ/4.7 114K miles. Recently the a/c has not been cooling properly.
Coolant charge is good and compressor comes on, but high side pressure
goes to ~275/300 then the fan kicks in but doesn't seem to pull hard
enough to cool the condenser, then the compressor kicks off. The cycle
continues......... Now, is the idiot designed hydraulic fan motor going bad,
and how can I test it? According to what I understand, the fan is controlled
0-100% by the PCM so if the sensor is sending an erroneous signal could that
be the culprit and how to test? If all else fails and the fan motor turns out
to be bad, is there an electric replacement?
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Old 05-16-2014, 10:12 PM
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Re: 04WJ Air Conditioner Issues

The refrigerant pressure is ok, but is the oil quantity in the refrigerant system ok as well? Too much oil will reduce the cooling capacity.
The hydraulic cooling fan is indeed controlled by the PCM. The PCM uses inputs from engine coolant temperature, transmission oil temperature, battery temperature and A/C system pressure to regulate the fan speed. A faulty A/C pressure sensor could cause the fan not to speed up and reduce the cooling capacity. Just to test the theorie of a faulty pressure sensor, you could remove the engine coolant temperature sensor connector ( in between alternator and A/C compressor), so that the fan goes to full speed. It should make quite some noise then. If the A/C is cooling ok now, then probably the A/C pressure sensor is faulty. (removing the coolant temperature sensor connector will give you the " check engine" light and a fault code set in the PCM, which needs to be reset after the connector is reconnected)
If the fan is not going to high speed, then there can be a problem with the fan system. A low steering pump pressure could also cause a low(er) fan speed.
I did read about some people who replaced the hydraulic cooling fan for a dual electric fan setup, but canīt tell much about this.
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Old 05-18-2014, 11:47 AM
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Re: 04WJ Air Conditioner Issues

Thanks Frango, I'll give it a try. Now, if I could only find out what/which
electric fan will interchange I'll be ready if the fan motor is failing.
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Old 05-18-2014, 02:47 PM
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Re: 04WJ Air Conditioner Issues

Quote:
Originally Posted by prsdrat View Post
Thanks Frango, I'll give it a try. Now, if I could only find out what/which
electric fan will interchange I'll be ready if the fan motor is failing.
It is quite rare for the hydraulic fan motor to fail. It can give problems with the control solenoid, but there is an alternative solenoid from Ford which can be used (would only require a different electrical connector)
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