Dead A/C & radiator fans, P1121 & P1116

My girlfriend picked up a used 2005 Prius about a year ago, and it's worked like a charm, for the most part.

The CEL used to blink on and off intermittently, and now it's on permanently. Had the codes read at Advance Auto, and P1121 and P1116 came up. I know that P1116 is often a companion code of P1121 / failed 3-way valve. The coolant reservoir next to the inverter has turbulence in it, so there's flow. I also have cabin heat.

Besides the CEL, here are the problems:
(1) The A/C has never worked,
(2) neither of the 2 radiator fans have ever turned on, to the best of my knowledge, and
(3) when the outdoor temperature is at 95F or higher, and the car isn't moving at highway speed (i.e., when it's sitting at a stoplight or moving slowly through town traffic), it gives me the Red Triangle of Death. I had that code read at one point, and I don't recall the number, but it was an overheating condition. Since it only happens when the car is not moving, I am 99% sure that the radiator fans not running are the cause of the overheat.

I know that I either have low coolant (though it doesn't appear low in the radiator or any of the reserviors) or a failed 3-way valve because of the P1121. I don't think I have air in the lines, because I see turbulence in the inverter reservoir.

My questions are these:
Could a P1121 / failed 3-way valve cause the A/C not to run?
Could a P1121 / failed 3-way valve cause the radiator fans not to run?
In other words, could I suddenly have working A/C and working radiator fans by replacing the 3-way valve?
ADD: Does a failed 3 way valve have a distinctive sound? It makes a series of clicks and woohwooh woohwooh sound, which I've been hearing forever, but never realized it was the 3 way valve.

 

Patrick, thanks for the input. I thought that I read somewhere that people's AC suddenly starred running cold when the 3 way valve was replaced. However, since my radiator fans don't run, I don't see how I'd have sufficient heat exchange to have cold air. Does a dead compressor or dead fans throw a code? Does the inverter or the valve make a clicking and woohwooh sound when functioning properly?

 

I agree that determining why the radiator fans do not operate is a top priority, since overheating will destroy the inverter, if ignored (albeit a diminishing one, since the weather is cooling off). Without it throwing codes, I imagine I will have to delve deeper into the service manual with a multimeter to figure it out. Any suggestions as to the best way to diagnose non-functional radiator fans that are not throwing codes would be greatly appreciated. The service manual is great, but also not the paragon of clarity (at least in the non-indexed PDF format I have it in), so if there's a thread or link that would help, I'd appreciate it.

It's been a while since I've thought about the A/C compressor, but isn't it in the lower left of the engine compartment? The A/C system is at pressure, just non-functional. The sound I am hearing is either coming from the 3-way valve or the inverter, which is upper right. I was just hoping to hear from someone who is either familiar with the sound (or non-sound) of a functioning 3-way valve vs. a non-functioning 3-way valve. Perhaps I'll need to capture the sound!

As for the A/C, I read elsewhere on here that a P1121, or more appropriately, a failed 3-way valve, could cause the A/C compressor to cut out, but it has never been clear to me why (something about conserving heat?). I apologize for the lack of links to support my statements - it's the first time I've posted on here, with a lot of lurking, and I don't quite have the knack of posting yet.