2002 S-Type. I just replaced the regulator and motor on the front driver' side window. The window was positioned half-up to accommodate the bolts. When finished I reconnected the battery and pushed the up button. The window closed. But when I pushed the down button nothing happened.
Where do I look first for the fault.
(At least the window is closed for the first time in months. Bring on the rain!)

 

I have an intermittent issue on my 2.5L 2004 X-Type with the same window (but it is on MY passenger side, which makes it the same window, as I am in Australia and the left side is where the passenger sits).
I have currently a bigger fish to fry on that X-Type, but once that is done, I will replace the window-regulator/motor (I already have the replacement part).

As for your question: I am electrical engineer, who specialized into switches, and I always suspect a switch fault first. Obviously, it can also be something else, a faulty switch is a possibility (one, where the contact for UP is working, but not the one for DOWN. But on the same note: I seem to faintly remember that I had your issue as well on my 2006 2.1L X-Type and I think a problem was with one of the plastic rollers/wheel, which guide the cable for the window.

Hence, if you do not here a window motor noise, I'd say. it is the switch.
But if you hear the window motor noise and the window still does not move, it sounds like the second issue - but still: Even if you do not hear anything, it could still be this, as the mechanism might be utterly wedged so that no motor noise is audible, because it just cannot turn due to to the cable being wedged.

So, this means: Removing the door trim again, removing the window glass again, removing the mechanism and assessing the mechanism.

Those flimsy plastic clips in the door trim will break, but you should be able to get them cheap on Aliexpress.

PS: I just realized that you question is about S-Type - but X-Type or S-Type probably does not make a difference here...

 

Simple answer? I don't think you have a fault?

You need to "clock" the regulator before installation. The system has the ability to adjust for this somewhat but it is limited.
What I do is operate the motor until it's at one end of it's range. Then I install it with the window all the way down. This usually gets things pretty close.
I have had to play with it a bit as sometimes I go the wrong way with the motor and installing it limits your access too.
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