Left Turn signal on dash stays illuminated...

I was in a fender bender the other day. The left turn signal out at the front bumper was broken out so I get the fast blinker sound inside the car when I try to give a left signal now. The right signal still works fine with regular tic tic sound. Why is the left turn signal permanently illuminated on the dash when I crank the car even when not attempting to give a signal? That was the position the blinker was in at the time I was hit, i.e., I was giving a left blinker. Is the Blazer designed to do this showing what indicators were on when wreck occurred? Last, how do I get it to turn off?
By the way, I bought this 2 door Blazer LS 2WD new in 2000 and have loved the little workhorse. Only 110k miles, clean inside and the only problem I have really had was the intake manifold gasket had to be replaced at my expense two years ago due to faulty GM design that allowed coolant leak (none into the engine though!). Oh and I blast out my heater coil in the dash with a homemade 3/4" hose and 1/2" hose I concocted since the heater coil was designed into the dash laying flat instead of standing up (clogs easily). I blast it out once a year and have great heat in winter.