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 can´t tell much about this.