Hello again everyone, My 2002 W203 C220 CDi has auto lights and I usually just leave the switch in Auto and the system to it's own devices, but I do keep an eye on what it is doing (or not doing). However, there are times when it appears reluctant to turn the lights on and also somewhat keen to switch them off again! This seems to be a little counter intuitive, I would expect them to be keen to switch on and reluctant to turn off! My limited experience of other cars is that they behave in the latter manner. My question is this, what, in a nutshell are the operating parameters of my system? Light level. Light level and auto wipers activity Light level, wiper activity and speed Anything else? Any permutation of the above? Yesterday I sallied forth in a heavy rain storm, at about mid day, but the lights did not switch on for a mile or two, while most oncoming traffic was well illuminated! (on a long bypassed and now very quiet former A road) Is there a possibility that the parameters can be reset by me, rather in the way that steering angle, heating flaps etc can be? Or by a genius with a STAR machine? I must stress that it always activates the lights immediately after starting if it is properly dark, also the Find Me & Light Me to the door functions via the fog lights both work well.