No blower is likely the blower control unit under the hood, in the fan housing. I have retrofitted EATC in my Ranger, and that's how I know a little about it. Look at my Cardomain site (link in my sig) and there is a bunch of info there.
But basically, it's like this: the fan speed is automatically controlled until you spin the little wheel for fan control on the right hand side. So if you punch the "Automatic" button, the fan should spin up when the engine comes up to temperature (winter) or with about 5 to 10 seconds (summer). If it's doesn't, that's not a manual control issue.
If you can't control the fan from the little wheel either, that pretty much clinches it.
Now, it CAN be the "main unit" -- but it seldom is.
Look here for some info: http://www.cardomain.com/ride/296394/15
-- that's one of my cardomain pages.
Here's a picture showing where the fan speed controller is located:
That's looking at the passengers side of the engine compartment, with the cruise control servo moved out of the way, and you're looking at the fan motor in the upper left. The place where you see some wires going, in the mid to lower right, is the fan controller location.
This is an install guide pic, so yours will obviously have all the wires connected and so on.
Chance are that this module is bad. It's a pretty common failure.
One other thing: does it only fail when he wants HEAT? That could be a problem with the sensors as well, or the network interface to the PCM. With the truck running, try this test:
Basically, what you do is press and hold the OFF button on the head unit, then press FLOOR while still holding down OFF. Now quickly release both buttons and press the AUTOMATIC button.
At this point a little line will appear to rotate in the middle of the display. This indicates testing is in progress.
The test can take what seems to be a long while when you're waiting for it! Just let it run and don't worry.
At the end, the display will begin flashing numbers, or it will simply light up everything on the display and halt.
If only "888" appears for the number, and everything else on the display is lit up, then you have passed the advanced self-test.
If there are numbers, write them down as they appear. Here's what they mean:
022, 024 - Blend door actuator shorted
025 - Blend door actuator not responding properly
030 - cabin temp sensor shorted (either wiring or bad sensor)
031 - cabin temp sensor not connected or failed (open circuit)
040, 042 - outside (ambient) sensor shorted (wiring or bad sensor)
041, 043 - outside (ambient) sensor not connected or failed (open circuit)
050, 052 - solar radiation sensor shorted
115, 125 - bad/no data from vehicle network (you'll get this always testing outside the vehicle)
This test doesn't test the fan speed controller because the unit can't really tell if it's responding or not -- there's no feedback from it.