[monkeyracer]

The law is vague, in the spectrum of light, white is all the colors together, and between white and amber could be any shade of the visible spectrum which would include blue.
However, the law is meant to be interpreted as "a white or amber light, or a color that is a shade of amber as light as white." or something to that effect.
If I were you, I'd skip hooking up the blue and save yourself the hassle. (I was pulled over passing through TX when I had my tire valve lights on, it was just a warning since I was from out of state and just passing through, but he said it would have been a ticket if I were a native.)