[the roadie]

The fan is indeed EV, but it doesn't go any faster with AC on. The PCM just makes sure it goes at 100% of engine RPM at idle even if the engine coolant doesn't need cooling. At last the 2005 PCM update to support the new fan clutch design did that.

For more details:
http://forums.trailvoy.com/showthread.php?t=19604

You said a scan tool says the fan isn't getting up to commanded RPM? Then you have a clutch or fuse or relay problem.

And if you have manually moved the driver's temp door, and the airflow isn't cold, you might have a mouse nest in the plenum or some other blockage. Heard of nests in the blower motor area, but that would be a first for temp door.

 

[the roadie]

That got me curious. We don't have a split system, that's right. We only have one evaporator, and it's centrally located. And the plenum looks like it's symmetrically designed so neither side will get preferential cooling. The digital system's sensors will accommodate a slight mismatch in airflow temp if that's true. But the experiment of removing the actuator and moving the temp door to full cold should have given the same temp as the passenger side.

Very odd, but it would require taking the plenum apart to see if the design could explain this observation. Or it could be a dust bunny buildup on the driver's side only because we don't have a cabin air filter.