Turn Signal Doesn't "flash" in dry weather.

What is your question?

My friend owns a Suburban, and she has to manually turn the turn-signal on and off, it doesn't do it by itself. However if it rains and car gets wet, the turn signal will work. As it starts to dry out, it stops working all over again. I should add that what I mean is it doesnt flash when you turn the signal on, and you have to turn the signal on and off just to make it work.