Of course : )
Changing color of a pixel is a basic mathematic multiplication : original color of the channel * target color of the channel. (there are 3 channels, RGB)
Black being an absence of color with a value of zero, then end calculation ends up being 0 * target color. And as you know, 0 times whatever = zero
The only potential solution here would be to pinpoint the name of the texture slot, change it, then apply your color.