...and ignition circuit bulbs (brake lights, indicators, reversing lights) cause the warning to stay on until the ignition is switched off whereas bulbs switched by the main lighting switch (head, side, tail, number plate) allow the warning to go out as soon as they are switched off.
Don't forget tail bulbs are 10W instead of the usual 5W.
'08 Chrysler 300CRD (MB OM 642 engine)
'95 E220 estate
'89 230TE (R.I.P.)