I noticed while diagnosing my warm AC (at idle) problem that the radiator fan is not coming on.

Actually, that is not entirely true. About every 1.5-2 minutes it turns a few times and then stops. I connected the wire going to the fan to my volt meter, and every couple of minutes the voltage increases to 7-8 volts before dropping back to zero. I took this to mean that the problem is probably not the fan. In fact, I connected the fan directly to the battery for a few seconds and it runs perfect.

Any idea on what I should check next?

Thanks!

Are you sure that this is actually a problem? Radiator fans are not like they were 20 years ago and spinning whenever the engine is running. They only turn on when needed, which is why there's a warning sticker under the hood on many cars stating that the fan could come on at any time, even if the engine is off. Do you have an overheating problem, or did you just notice the fan not always turning only when you started looking into the A/C problem?

Well, I'm not 100 % certain that this is my AC problem, but I'm pretty sure. One reason I think this is because I had two occasions where the car has overheated (as you suggested).

Also, I measured the high and low side pressure on the refrigerant after driving around town. Both readings were on the high side. I first thought that someone had overcharged the system, but when I measured the pressure the next morning, after idling for only a couple of minutes, the AC pressure was right where it needed to be. I think this is because the fan is not cooling the refrigerant on the high pressure side to the proper temperature - causing the pressure to be higher than the suggested pressure.

I'm not an expert here, but I don't think the radiator fan has anything to do with the A/C refrigerant as the refrigerant does not need cooling. It it compressed to high pressure by the compressor and then cools at it is re-expanded. Air is blown over the coils or whatever where the refrigerant expands and then into the passenger compartment. Hence the cooling.

The radiator cools the engine coolant and the transmission fluid (at least it used to). I think your noticing the radiator fan possibly having an issue while trying to diagnose your A/C problem is just a coincidence.

Thanks for the help.

My understanding of the AC system is that after passing through the compressor, the refrigerant is cooled using a portion of the radiator (and is referred to as a condenser in this case). The condensed refrigerant then travels through a throttling valve and then into the evaporator where it cools the cabin air. If sufficient air is not passing through the radiator, then the refrigerant is not cooled and does not reach the correct cold temperature in the evaporator.

At least, this is my understanding of the AC system and why I've attributed my AC problem - AC works fine when I'm driving but works very poorly when the car is simply idling - to the radiator fan.

I think you're right.

After reading the Mitchell manual and looking at the electrical diagram for the fan motors on a 2005 Freestyle, the fan operation remains an enigma to me. The manual refers to a FAN CONTROL MODULE but doesn't show it on any diagram and doesn't list it in the Electrical Component Locations table. However, the fan unit appears as a "black box" on the diagram. It has Pin 1 (green wire) going to Fuse 8 (60 Amp) in the Battery Junction Box (under hood). Pin 4 is connected to a Lt Blu wire that goes to Pin 14 on the Powertrain Control Module (PCM) and Pin 2 is connected to a black wire that goes to Ground. I ASS-u-me that the PCM sends a signal to the Fan Control Module located somewhere in the Fan Assembly and that it activates a relay that applies the 12 volts from Fuse 8 via Pin 1 to the Fan Motors to turn them on. Since you stated that the fans ran when you connected 12 volts directly to the Fans (Pin 1 ???) it would appear that the PCM and Fan Control Module are operating correctly and that you have a problem with the 12V power to the fan. If you connected 12v directly to Pin 4 it would appear that you have a bad PCM or a bad connection between the PCM and the Fan assembly. May be a high resistance connection somewhere in the circuit or an intermittent open circuit. Hope this helps. You didn't say what model year freestyle you have.

If you start the car on a cold day,with the heater on, it will not warm up to a comfortable temp until you start driving. I think the same applies to cooling on a hot day.

I think the Original poster's problem sounds a lot like the failed A/C compressor issue some have been posting about on here recently. In those cases it does not cool at idle but does when driving at speed. Replacement of the compressor or valve on the compressor has been the fix.

Wheelman - You might be right to an extent, but my AC doesn't work well if I'm at a stoplight or just driving around town. I have to actually travel above 35 mph for a few minutes before I notice any improvement.

Mike - I also wondered if it wasn't the compressor issue I read about in another thread. I don't think that would explain why my radiator fan is not coming on, though. In fact, the engine slowly heats up if I let the car idle in my driveway with the AC on. Surely, the fan should kick on at some point regardless of the condition of the AC compressor.

Nkenn - It sounds like the Mitchell manual may have the information I need. My Freestyle is an '06.

There is a connector with three wires coming from the main wiring harness to the fan shroud. These three wires connect to a silver box (Fan Control Module???) mounted on the fan shroud that has two wires (red/black) going to radiator fan #1 and two wires (red/black) going to radiator fan #2. From what I've seen online, it looks like the shroud, both fans, and the fan control module are sold as a single item ($180). I hate to replace the fans and shroud since they're not bad, but I may have to do this just to get the fan control module. Before doing so, I'd like to confirm the fan control module is bad.

I've checked the voltage coming from the fan control module to the fan, and it is clearly not where it should be. I'm still not sure if this is because the fan control module itself is bad or the signal going to the fan control module is bad. I've checked the 60 amp fuse you referred to and it is good. Beyond this, I'm not sure how to check the signal going to the fan control module. Ultimately, I need to decide whether the problem is the PCM or the fan control module. Any suggestions?

I guess I can check the voltage across Pin 1 and Pin 2. I'm assuming that this voltage should always be 12 volts? What kind of signal (voltage) would come from the PCM, Pin4? How does the PCM signal the fan control module to turn on fan #1 or both fan #1 and fan #2? As you can tell, I'm at a real loss at this point.

Thanks for all the help guys!

Well, I finally became desperate enough and decided to replace the entire fan shroud assembly. (I suspected the problem was the silver box mounted to the fan shroud, but I couldn't seem to find just this part.) I removed the old fan shroud assembly and noticed that the radiator fan (on the driver's side) had a couple strips of foam lodged in the blades preventing it from turning. I removed the foam, reconnected the fan to the wiring harness, and it works!!!

I'm assuming that the car tried to power to two fans every few minutes, but since one of the two radiator fans was stuck, the car was cutting power to both fans. Maybe this explains why every few minutes the A/C fan (passenger side) would turn a few times and then stop.

Well, anyways, an easy repair for something I worried about for several weeks.

Cool! I love repairs that turn out to be that simple and cheap.