My hair is dark brown but when use my hair straightener my hair turns to a golden blonde color, HELP!?

I don't like the golden color! I use heat protect by V05, so why is this happening?My hair is dark brown but when use my hair straightener my hair turns to a golden blonde color, HELP!?
I think it might have to do with the heat you're applying to your strands. Long time ago there was this gel, and i think its still around, Lighting Gel, all you did was put in on and go out in the sun and it didn't matter what hair color you were it would turn it from orange to light light blonde. So it might be a mixture of the shampoo and the application of heat from your hair straightener, try a lower heat setting that might work, if not maybe try switching your shampoo.My hair is dark brown but when use my hair straightener my hair turns to a golden blonde color, HELP!?
Try it w/o the VO5, just to make sure it isn't that product bringing in some highlights....





Sounds like it might be pretty though.