Charon,
I'm going to shoot in the dark here, since I haven't looked at my VX, but when I had the engine replaced the shop said that there was a broken wire at the power steering pump (I think that's where it was). They said that due to the corrosion on the broken wire end, it had probably been broken for a while. They ended up tracing it back to a sensor on or around the power steering pump, and it was tough to find since the wire had broken off right at the sensor itself. Apparently, the sensor monitors the engine speed and the power steering pump. Since the pump puts a draw on the engine when it is working the sensor senses when the steering is being used (thus using the pump) and will bump up the engine RPM's if they aren't high enough already, to make up for the load that the power steering pump adds to the engine.
As an example, if you are in park with the engine idling, and you turn the steering wheel, the engine RPM's should jump up a bit since the power steering pump is in use. If you are going down the highway, or cruising around a parking lot and you turn the wheel, chances are the RPM's won't bump up due to the fact that the engine is probably already at a high enough RPM.
The shop ordered a new sensor (to the tune of +/-$200) and installed it when they installed the new engine. To tell you the truth I haven't noticed a difference with the new sensor. Due to the corrosion on the raw wire that sensor probably wasn't working for a while and I don't think that it has done any damage to the pump. I did multiple trips to Moab, where there is a lot of low speed, low RPM turning, and I didn't find it hard to get around.
I will try and remember to take a look at my VX when I get home and see if I can locate that power steering sensor and see what color wire is coming out of it.
"The major difference between a thing that might go wrong and a thing that cannot possibly go wrong is that when a thing that cannot possibly go wrong goes wrong, it usually turns out to be impossible to get at or repair."
-Douglas Adams, Mostly Harmless