Aux fan not working - Does this make ac to not work

white_335i · #1 07-06-2018, 05:59 PM

Hello,

As the subject line says, the aux fan is not kicking on when I turn on the AC. Also, the AC is not blowing cold air. The clutch on the compressor turns on when I turn on the AC and there is freeon in the lines.

I drove the car around the block to see if it helps with AC, but no luck...

Also want to note that I have the fan, fan clutch and the fan shroud with the sensor out of the car.. Does that make the aux fan not to work?

Thoughts on why the ac is not blowing cold air? Thanks in advance for your help!!

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Overboost · #2 07-06-2018, 06:45 PM

When my aux fan failed the compressor clutch would not engage so I'm not sure what yours is doing? You should be able to unplug the AC pressure switch and the fan show run full speed if it is good.

upallnight · #3 07-07-2018, 06:24 AM

Check the 50 amp fuse in the glove box. If that is blown, your aux fan is blown. I'm surprised that the ac compressor is engaging, but the ac is not working. The pulley will be spinning but is the clutch plate engaged? Are you misreading the spinning pulley that the compressor is engaged?

white_335i · #4 07-26-2018, 11:54 PM

Quote:

Originally Posted by Overboost

When my aux fan failed the compressor clutch would not engage so I'm not sure what yours is doing? You should be able to unplug the AC pressure switch and the fan show run full speed if it is good.

Thanks Overboost. Finally had a chance to unplug the ac pressure switch and the aux fan came on at full speed. Does that mean the pressure switch is bad? If yes, is it a easy replacement? Meaning, can I replace it without evacuating the freeon? I've read that the line may have a shrader valve and when the switxh is removed, the freeon,doesnt escape.. Thoughts? Thanks

white_335i · #5 07-26-2018, 11:57 PM

Quote:

Originally Posted by upallnight

Check the 50 amp fuse in the glove box. If that is blown, your aux fan is blown. I'm surprised that the ac compressor is engaging, but the ac is not working. The pulley will be spinning but is the clutch plate engaged? Are you misreading the spinning pulley that the compressor is engaged?

Hi Upallnight, all the fuses check out.. It is the compressor clutch engaging.. Like Overboost had suggested, i had unplugged the wire to the ac pressure switch and the aux fan came on at high speed. Will get a new switch and go from there. Thanks..

wpoll · #6 07-27-2018, 01:41 AM

I don't think this test necessarily indicates a bad switch - but it does tell you that your fan is good.

The HP switch may be fine and some other issue is causing the AC-NoGo situation.

upallnight · #7 07-27-2018, 10:51 AM

Quote:

Originally Posted by white_335i

Hi Upallnight, all the fuses check out.. It is the compressor clutch engaging.. Like Overboost had suggested, i had unplugged the wire to the ac pressure switch and the aux fan came on at high speed. Will get a new switch and go from there. Thanks..

Since the compressor is engaging, but there's no cold air from the vents, you will need to find out what the pressures are in the system, the low side pressure and the high side pressure and the ambient temperature when these pressures were read.

white_335i · #8 07-29-2018, 06:02 PM

Quote:

Originally Posted by upallnight

Since the compressor is engaging, but there's no cold air from the vents, you will need to find out what the pressures are in the system, the low side pressure and the high side pressure and the ambient temperature when these pressures were read.

Hi Upallnight, I am waiting for the manifold guages to showup, but in the meantime, picked up a can of freeon that has a guage. Connected it to the low side and the the guage is in the "green" 40lb ish, outside temp was 96.. Same reading with compressor on and off. So, this is telling me that the system is full and has no leaks.

I had also used DIS to force/turn on the ac compressor and I am 100% sure that the clutch is engaging.

Also, another interesting thing is, I feel like the vents are blowing hot air as if the temp on the climate control unit is set to high/heat..But, the temp is set to 60... Does this indicate that the heater control valve is open?

Thoughts?

upallnight · #9 07-29-2018, 07:25 PM

Quote:

Originally Posted by white_335i

Hi Upallnight, I am waiting for the manifold guages to showup, but in the meantime, picked up a can of freeon that has a guage. Connected it to the low side and the the guage is in the "green" 40lb ish, outside temp was 96.. Same reading with compressor on and off. So, this is telling me that the system is full and has no leaks.

I had also used DIS to force/turn on the ac compressor and I am 100% sure that the clutch is engaging.

Also, another interesting thing is, I feel like the vents are blowing hot air as if the temp on the climate control unit is set to high/heat..But, the temp is set to 60... Does this indicate that the heater control valve is open?

Thoughts?

With the compressor off, the reading should be higher. When the compressor is running it is drawing the refrigerant through the expansion valve which will cause the liquid refrigerant to expand into a gas and as it expands into a gas the refrigerant gets cold.

The fact that the pressure is the same whether the compressor is running or not leads me to believe that either the compressor is a variable displacement compressor and it is not working properly or you are not able to tell whether the compressor is engaging or not engaging. A manifold gauge set connected to the low side and high side will be more informative.

g300d · #10 07-29-2018, 08:03 PM

^pretty much this, pending any new info I would say your compressor is shot.

For the 3.0 the variable displacement compressors came in with the facelift.

With these compressors the clutch can engage but have no compression. No compression = no pressure, no fan.

This throws a lot of people off (including me). I had the same problem, but intermittent.

I replaced my compressor and that solved it for me.

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