Let's explain to you how the system works, ok? You have to fix this pretty much on your own (since we are not there) and the first step in fixing it is understanding how it WORKS. From a post in another thread where I was trying to help a guy, I added the italics for this thread:

It works like this:
FCM = Fan Control Module
PTCM = Power Train Control Module

On the FCM, there are two HEAVY wires that supply power to it, one is, of course, 12 volts, and one is ground. There are two HEAVY output wires, too - they go to the fan motor and are power and ground.

There is one single, small wire, it is GY (Gray) and is the two-way data link from the PTCM to the FCM.
There is another small wire, it is PK/RD (pink - red) and is the ignition switch input to the module.

Ok......

There is a single wire running from the PTCM to the FCM. This wire has 12 volts on it, the PTCM pulls this wire to ground in a series of pulses, the WIDER the pulses, the faster the FCM makes the fan run. (It does this by sending pulses of 12 volts to the fan motor, your meter will show 4 to 12 volts, but that's because your meter is averaging the pulses - DC motors are not usually run on low voltage for low speed, they are run on NORMAL voltage that is pulsed to get the right speed). Periodically, the FCM also pulls the line to ground - this tells the PTCM that the FCM is still working.

The PTCM turns the light on if it does not see the pulses coming back from the FCM.

Also, if the FCM does not see the pulses from the PTCM, it assumes something is wrong (which is the case) and that the engine's temperature is unknown (which is also true) so the FCM turns the fan on all the way. If the light is on and the fan is running full speed, there is a communication breakdown between the modules.

If the light is on and the fan is not working, then the big fuse to the FCM isprobably blown OR the FCM is bad. (I do not think the FCM can sense a bad fan motor.)

You can always unplug the fan motor from the FCM, the connector is clipped to the radiator support on the driver's side - use wires with the end stripped off and see if you can jumper the fan motor directly to the battery. If the motor turns, the FCM is bad. If the motor does NOT turn, the motor is bad.

Using a meter:
Make sure you have 12 volts on that PK/RD wire.
Make sure you have 12 volts on the heavy lead going into the FCM (and I think you do, or you'd have a radiator light).
Make sure your heavy ground input is ok (But, again, if it wasn't, I'd suspect you'd have a light on)

It SOUNDS like the 12 volts is not making it to the fan motor harness. Ground your meter well and probe the 12 side to the fan AND the ground side. YOu should see pulses that average on a Digital meter to something about 4 volts on the hot lead going to the fan and less than .1 volts on the round lead coming back.

As an acid test you can CUT the Gray wire (do this so that you have enough wire to splice it back together). By cutting this wire, you will cause the FCM and PTCM to loose contact and:

1) The PTCM will go into alarm and light the radiator light - telling you that you have a cooling system problem.
2) The FCM will go into emergency mode, because it has lost contact with the PTCM - and will fire the fan off at 100% full speed. This means the voltage to the fan will be 12 volts, up to 14 if the engine is running!

NOW you can find your problem. I STRONGLY suspect there is a corroded, loose or bad connection between the fan motor and the FCM. Again, if the FCM does not have the power it needs, it won't likely be able to pulse the PTCM and the PTCM will light the light - and you say the radiator light is not on!

I"m thinking cutting that wire will tell you more than substituting parts. But I DO NOT believe you have two bad fan motors OR two bad FCMs.... gottta be wiring. If you turn the A/C on, the fan runs slow, about 150 rpm or mabye 200 rpm. If that isn't happening, and the radiator light is not on, gotta be a bad motor or wiring from FCM to Motor.

Unless I am missing something. But even if the temperature sensor is lying about engine temp, turning the A/C on HAS TO RUN THE FAN. THere is no way around this.