I am changing out the front and rear speakers of my truck but I do not know which wires are negative and positive. They are gray and yellow coloring I believe. I cant find anything saying which is which for the life of me. If anyone knows it would be greatly appreciated. Thanks!

 

sounds like your gray is your neg and your yellow is your +

 

As long as you connect the same color wire to positive or negative at both ends it wont matter which you use for which.