Not sure what a "drivers drop light" is, but if you are referring to the drivers window, it may be the "jam sensor" kicking in. These window motors have some kind of sensor,which, if it detects resistance, i.e. fingers caught in the window when going up, the motor stops and reverses the window a bit - so as to allow the jammed fingers to be removed. If this is what you are experiencing, I'd suggest cleaning the runners of the window mechanism getting rid of old dirty dried up grease and regreasing with new grease as old dry grease adds to resistance therefore blagging the anti-jam feature to kick in.
It seemed to do the trick for me (I used to multi-press my window switch to get my drivers window up before i fixed my blue 1990 Carlton RIP).
It must be the drivers one which goes first through as its used a lot therefore picking up more dirt in its greased areas.
Also ensure window runners are correctly aligned if grease doesnt do the trick.
*** WARNING ***Bear in mind though that the jam sensors sometimes dont work - as a colleague of mine unwittingly found out when demonstrating the mechanism to me in the late 80s. His fingers were quite sore for a few days after.
If you need to test, try something squishy-ish but not living - perhaps a teddy bear or something.
