Diff lock light - sometimes works

Afternoon all. I have noticed recently that when selecting diff lock, the warning light comes on and then off (when taking out of diff lock) and then when re-selecting, it won't come on. Is thi slikely to be a dirty connection, a failing switch or something out of adjustment please? I have searched the forum, but not been lucky, so the answer may be out there, I just can't find it. Thank you for any on subject input.

i had the same problem with mine and i removed the switch, cleaned all the rubbish off it and put it back, its been ok since.

Thank you, I will give it a try. It doesn't get used all that much so maybe that's all it is.